.. changelog_imports::
.. include:: changelog_12.rst
:start-line: 5
.. include:: changelog_11.rst
:start-line: 5
.. changelog::
:version: 1.3.25
:include_notes_from: unreleased_13
.. changelog::
:version: 1.3.24
:released: March 30, 2021
.. change::
:tags: bug, schema
:tickets: 6152
Fixed bug first introduced in as some combination of :ticket:`2892`,
:ticket:`2919` nnd :ticket:`3832` where the attachment events for a
:class:`_types.TypeDecorator` would be doubled up against the "impl" class,
if the "impl" were also a :class:`_types.SchemaType`. The real-world case
is any :class:`_types.TypeDecorator` against :class:`_types.Enum` or
:class:`_types.Boolean` would get a doubled
:class:`_schema.CheckConstraint` when the ``create_constraint=True`` flag
is set.
.. change::
:tags: bug, schema, sqlite
:tickets: 6007
:versions: 1.4.0
Fixed issue where the CHECK constraint generated by :class:`_types.Boolean`
or :class:`_types.Enum` would fail to render the naming convention
correctly after the first compilation, due to an unintended change of state
within the name given to the constraint. This issue was first introduced in
0.9 in the fix for issue #3067, and the fix revises the approach taken at
that time which appears to have been more involved than what was needed.
.. change::
:tags: bug, orm
:tickets: 5983
:versions: 1.4.0
Removed very old warning that states that passive_deletes is not intended
for many-to-one relationships. While it is likely that in many cases
placing this parameter on a many-to-one relationship is not what was
intended, there are use cases where delete cascade may want to be
disallowed following from such a relationship.
.. change::
:tags: bug, postgresql
:tickets: 5989
:versions: 1.4.0
Fixed issue where using :class:`_postgresql.aggregate_order_by` would
return ARRAY(NullType) under certain conditions, interfering with
the ability of the result object to return data correctly.
.. change::
:tags: bug, schema
:tickets: 5919
:versions: 1.4.0
Repaired / implemented support for primary key constraint naming
conventions that use column names/keys/etc as part of the convention. In
particular, this includes that the :class:`.PrimaryKeyConstraint` object
that's automatically associated with a :class:`.schema.Table` will update
its name as new primary key :class:`_schema.Column` objects are added to
the table and then to the constraint. Internal failure modes related to
this constraint construction process including no columns present, no name
present or blank name present are now accommodated.
.. change::
:tags: bug, schema
:tickets: 6071
:versions: 1.4.3
Adjusted the logic that emits DROP statements for :class:`_schema.Sequence`
objects among the dropping of multiple tables, such that all
:class:`_schema.Sequence` objects are dropped after all tables, even if the
given :class:`_schema.Sequence` is related only to a :class:`_schema.Table`
object and not directly to the overall :class:`_schema.MetaData` object.
The use case supports the same :class:`_schema.Sequence` being associated
with more than one :class:`_schema.Table` at a time.
.. change::
:tags: bug, orm
:tickets: 5952
:versions: 1.4.0
Fixed issue where the process of joining two tables could fail if one of
the tables had an unrelated, unresolvable foreign key constraint which
would raise :class:`_exc.NoReferenceError` within the join process, which
nonetheless could be bypassed to allow the join to complete. The logic
which tested the exception for significance within the process would make
assumptions about the construct which would fail.
.. change::
:tags: bug, postgresql, reflection
:tickets: 6161
:versions: 1.4.4
Fixed issue in PostgreSQL reflection where a column expressing "NOT NULL"
will supersede the nullability of a corresponding domain.
.. change::
:tags: bug, engine
:tickets: 5929
:versions: 1.4.0
Fixed bug where the "schema_translate_map" feature failed to be taken into
account for the use case of direct execution of
:class:`_schema.DefaultGenerator` objects such as sequences, which included
the case where they were "pre-executed" in order to generate primary key
values when implicit_returning was disabled.
.. change::
:tags: bug, orm
:tickets: 6001
:versions: 1.4.0
Fixed issue where the :class:`_mutable.MutableComposite` construct could be
placed into an invalid state when the parent object was already loaded, and
then covered by a subsequent query, due to the composite properties'
refresh handler replacing the object with a new one not handled by the
mutable extension.
.. change::
:tags: bug, types, postgresql
:tickets: 6023
:versions: 1.4.3
Adjusted the psycopg2 dialect to emit an explicit PostgreSQL-style cast for
bound parameters that contain ARRAY elements. This allows the full range of
datatypes to function correctly within arrays. The asyncpg dialect already
generated these internal casts in the final statement. This also includes
support for array slice updates as well as the PostgreSQL-specific
:meth:`_postgresql.ARRAY.contains` method.
.. change::
:tags: bug, mssql, reflection
:tickets: 5921
Fixed issue regarding SQL Server reflection for older SQL Server 2005
version, a call to sp_columns would not proceed correctly without being
prefixed with the EXEC keyword. This method is not used in current 1.4
series.
.. changelog::
:version: 1.3.23
:released: February 1, 2021
.. change::
:tags: bug, ext
:tickets: 5836
Fixed issue where the stringification that is sometimes called when
attempting to generate the "key" for the ``.c`` collection on a selectable
would fail if the column were an unlabeled custom SQL construct using the
``sqlalchemy.ext.compiler`` extension, and did not provide a default
compilation form; while this seems like an unusual case, it can get invoked
for some ORM scenarios such as when the expression is used in an "order by"
in combination with joined eager loading. The issue is that the lack of a
default compiler function was raising :class:`.CompileError` and not
:class:`.UnsupportedCompilationError`.
.. change::
:tags: bug, postgresql
:tickets: 5645
For SQLAlchemy 1.3 only, setup.py pins pg8000 to a version lower than
1.16.6. Version 1.16.6 and above is supported by SQLAlchemy 1.4. Pull
request courtesy Giuseppe Lumia.
.. change::
:tags: bug, postgresql
:tickets: 5850
Fixed issue where using :meth:`_schema.Table.to_metadata` (called
:meth:`_schema.Table.tometadata` in 1.3) in conjunction with a PostgreSQL
:class:`_postgresql.ExcludeConstraint` that made use of ad-hoc column
expressions would fail to copy correctly.
.. change::
:tags: bug, sql
:tickets: 5816
Fixed bug where making use of the :meth:`.TypeEngine.with_variant` method
on a :class:`.TypeDecorator` type would fail to take into account the
dialect-specific mappings in use, due to a rule in :class:`.TypeDecorator`
that was instead attempting to check for chains of :class:`.TypeDecorator`
instances.
.. change::
:tags: bug, mysql, reflection
:tickets: 5860
Fixed bug where MySQL server default reflection would fail for numeric
values with a negation symbol present.
.. change::
:tags: bug, oracle
:tickets: 5813
Fixed regression in Oracle dialect introduced by :ticket:`4894` in
SQLAlchemy 1.3.11 where use of a SQL expression in RETURNING for an UPDATE
would fail to compile, due to a check for "server_default" when an
arbitrary SQL expression is not a column.
.. change::
:tags: usecase, mysql
:tickets: 5808
Casting to ``FLOAT`` is now supported in MySQL >= (8, 0, 17) and
MariaDb >= (10, 4, 5).
.. change::
:tags: bug, mysql
:tickets: 5898
Fixed long-lived bug in MySQL dialect where the maximum identifier length
of 255 was too long for names of all types of constraints, not just
indexes, all of which have a size limit of 64. As metadata naming
conventions can create too-long names in this area, apply the limit to the
identifier generator within the DDL compiler.
.. change::
:tags: bug, oracle
:tickets: 5812
Fixed bug in Oracle dialect where retrieving a CLOB/BLOB column via
:meth:`_dml.Insert.returning` would fail as the LOB value would need to be
read when returned; additionally, repaired support for retrieval of Unicode
values via RETURNING under Python 2.
.. change::
:tags: bug, mysql
:tickets: 5821
Fixed deprecation warnings that arose as a result of the release of PyMySQL
1.0, including deprecation warnings for the "db" and "passwd" parameters
now replaced with "database" and "password".
.. change::
:tags: bug, mysql
:tickets: 5800
Fixed regression from SQLAlchemy 1.3.20 caused by the fix for
:ticket:`5462` which adds double-parenthesis for MySQL functional
expressions in indexes, as is required by the backend, this inadvertently
extended to include arbitrary :func:`_sql.text` expressions as well as
Alembic's internal textual component, which are required by Alembic for
arbitrary index expressions which don't imply double parenthesis. The
check has been narrowed to include only binary/ unary/functional
expressions directly.
.. changelog::
:version: 1.3.22
:released: December 18, 2020
.. change::
:tags: bug, oracle
:tickets: 5784
:versions: 1.4.0b2
Fixed regression which occurred due to :ticket:`5755` which implemented
isolation level support for Oracle. It has been reported that many Oracle
accounts don't actually have permission to query the ``v$transaction``
view so this feature has been altered to gracefully fallback when it fails
upon database connect, where the dialect will assume "READ COMMITTED" is
the default isolation level as was the case prior to SQLAlchemy 1.3.21.
However, explicit use of the :meth:`_engine.Connection.get_isolation_level`
method must now necessarily raise an exception, as Oracle databases with
this restriction explicitly disallow the user from reading the current
isolation level.
.. changelog::
:version: 1.3.21
:released: December 17, 2020
.. change::
:tags: bug, orm
:tickets: 5774
:versions: 1.4.0b2
Added a comprehensive check and an informative error message for the case
where a mapped class, or a string mapped class name, is passed to
:paramref:`_orm.relationship.secondary`. This is an extremely common error
which warrants a clear message.
Additionally, added a new rule to the class registry resolution such that
with regards to the :paramref:`_orm.relationship.secondary` parameter, if a
mapped class and its table are of the identical string name, the
:class:`.Table` will be favored when resolving this parameter. In all
other cases, the class continues to be favored if a class and table
share the identical name.
.. change::
:tags: sqlite, usecase
:tickets: 5685
Added ``sqlite_with_rowid=False`` dialect keyword to enable creating
tables as ``CREATE TABLE … WITHOUT ROWID``. Patch courtesy Sean Anderson.
.. change::
:tags: bug, sql
:tickets: 5691
A warning is emitted if a returning() method such as
:meth:`_sql.Insert.returning` is called multiple times, as this does not
yet support additive operation. Version 1.4 will support additive
operation for this. Additionally, any combination of the
:meth:`_sql.Insert.returning` and :meth:`_sql.ValuesBase.return_defaults`
methods now raises an error as these methods are mutually exclusive;
previously the operation would fail silently.
.. change::
:tags: bug, mssql
:tickets: 5751
Fixed bug where a CREATE INDEX statement was rendered incorrectly when
both ``mssql-include`` and ``mssql_where`` were specified. Pull request
courtesy @Adiorz.
.. change::
:tags: bug, postgresql, mysql
:tickets: 5729
:versions: 1.4.0b2
Fixed regression introduced in 1.3.2 for the PostgreSQL dialect, also
copied out to the MySQL dialect's feature in 1.3.18, where usage of a non
:class:`_schema.Table` construct such as :func:`_sql.text` as the argument
to :paramref:`_sql.Select.with_for_update.of` would fail to be accommodated
correctly within the PostgreSQL or MySQL compilers.
.. change::
:tags: bug, mssql
:tickets: 5646
Added SQL Server code "01000" to the list of disconnect codes.
.. change::
:tags: usecase, postgresql
:tickets: 5604
:versions: 1.4.0b2
Added new parameter :paramref:`_postgresql.ExcludeConstraint.ops` to the
:class:`_postgresql.ExcludeConstraint` object, to support operator class
specification with this constraint. Pull request courtesy Alon Menczer.
.. change::
:tags: bug, mysql, reflection
:tickets: 5744
:versions: 1.4.0b2
Fixed issue where reflecting a server default on MariaDB only that
contained a decimal point in the value would fail to be reflected
correctly, leading towards a reflected table that lacked any server
default.
.. change::
:tags: bug, orm
:tickets: 5664
Fixed bug in :meth:`_query.Query.update` where objects in the
:class:`_ormsession.Session` that were already expired would be
unnecessarily SELECTed individually when they were refreshed by the
"evaluate"synchronize strategy.
.. change::
:tags: usecase, oracle
:tickets: 5755
Implemented support for the SERIALIZABLE isolation level for Oracle
databases, as well as a real implementation for
:meth:`_engine.Connection.get_isolation_level`.
.. seealso::
:ref:`oracle_isolation_level`
.. change::
:tags: mysql, sql
:tickets: 5696
Added missing keywords to the ``RESERVED_WORDS`` list for the MySQL
dialect: ``action``, ``level``, ``mode``, ``status``, ``text``, ``time``.
Pull request courtesy Oscar Batori.
.. change::
:tags: bug, orm
:tickets: 5737
:versions: 1.4.0b2
Fixed bug involving the ``restore_load_context`` option of ORM events such
as :meth:`_ormevent.InstanceEvents.load` such that the flag would not be
carried along to subclasses which were mapped after the event handler were
first established.
.. change::
:tags: bug, sql
:tickets: 5656
Fixed structural compiler issue where some constructs such as MySQL /
PostgreSQL "on conflict / on duplicate key" would rely upon the state of
the :class:`_sql.Compiler` object being fixed against their statement as
the top level statement, which would fail in cases where those statements
are branched from a different context, such as a DDL construct linked to a
SQL statement.
.. change::
:tags: mssql, sqlite, reflection
:tickets: 5661
Fixed issue with composite primary key columns not being reported
in the correct order. Patch courtesy @fulpm.
.. changelog::
:version: 1.3.20
:released: October 12, 2020
.. change::
:tags: bug, orm
:tickets: 4428
An :class:`.ArgumentError` with more detail is now raised if the target
parameter for :meth:`_query.Query.join` is set to an unmapped object.
Prior to this change a less detailed ``AttributeError`` was raised.
Pull request courtesy Ramon Williams.
.. change::
:tags: bug, mysql
:tickets: 5568
The "skip_locked" keyword used with ``with_for_update()`` will emit a
warning when used on MariaDB backends, and will then be ignored. This is
a deprecated behavior that will raise in SQLAlchemy 1.4, as an application
that requests "skip locked" is looking for a non-blocking operation which
is not available on those backends.
.. change::
:tags: bug, engine
:tickets: 5599
Fixed issue where a non-string object sent to
:class:`_exc.SQLAlchemyError` or a subclass, as occurs with some third
party dialects, would fail to stringify correctly. Pull request
courtesy Andrzej Bartosiński.
.. change::
:tags: bug, sql
:tickets: 5644
Fixed issue where the ``pickle.dumps()`` operation against
:class:`_expression.Over` construct would produce a recursion overflow.
.. change::
:tags: postgresql, usecase
:tickets: 4392
The psycopg2 dialect now support PostgreSQL multiple host connections, by
passing host/port combinations to the query string. Pull request courtesy
Ramon Williams.
.. seealso::
:ref:`psycopg2_multi_host`
.. change::
:tags: bug, mysql
:tickets: 5617
Fixed bug where an UPDATE statement against a JOIN using MySQL multi-table
format would fail to include the table prefix for the target table if the
statement had no WHERE clause, as only the WHERE clause were scanned to
detect a "multi table update" at that particular point. The target
is now also scanned if it's a JOIN to get the leftmost table as the
primary table and the additional entries as additional FROM entries.
.. change::
:tags: bug, postgresql
:tickets: 5518
Adjusted the :meth:`_types.ARRAY.Comparator.any` and
:meth:`_types.ARRAY.Comparator.all` methods to implement a straight "NOT"
operation for negation, rather than negating the comparison operator.
.. change::
:tags: bug, pool
:tickets: 5582
Fixed issue where the following pool parameters were not being propagated
to the new pool created when :meth:`_engine.Engine.dispose` were called:
``pre_ping``, ``use_lifo``. Additionally the ``recycle`` and
``reset_on_return`` parameter is now propagated for the
:class:`_engine.AssertionPool` class.
.. change::
:tags: bug, ext, associationproxy
:tickets: 5541, 5542
An informative error is now raised when attempting to use an association
proxy element as a plain column expression to be SELECTed from or used in a
SQL function; this use case is not currently supported.
.. change::
:tags: bug, sql
:tickets: 5618
Fixed bug where an error was not raised in the case where a
:func:`_sql.column` were added to more than one :func:`_sql.table` at a
time. This raised correctly for the :class:`_schema.Column` and
:class:`_schema.Table` objects. An :class:`_exc.ArgumentError` is now
raised when this occurs.
.. change::
:tags: bug, orm
:tickets: 4589
Fixed issue where using a loader option against a string attribute name
that is not actually a mapped attribute, such as a plain Python descriptor,
would raise an uninformative AttributeError; a descriptive error is now
raised.
.. change::
:tags: mysql, usecase
:tickets: 5462
Adjusted the MySQL dialect to correctly parenthesize functional index
expressions as accepted by MySQL 8. Pull request courtesy Ramon Williams.
.. change::
:tags: bug, engine
:tickets: 5632
Repaired a function-level import that was not using SQLAlchemy's standard
late-import system within the sqlalchemy.exc module.
.. change::
:tags: change, mysql
:tickets: 5539
Add new MySQL reserved words: ``cube``, ``lateral`` added in MySQL 8.0.1
and 8.0.14, respectively; this indicates that these terms will be quoted if
used as table or column identifier names.
.. change::
:tags: bug, mssql
:tickets: 5592
Fixed issue where a SQLAlchemy connection URI for Azure DW with
``authentication=ActiveDirectoryIntegrated`` (and no username+password)
was not constructing the ODBC connection string in a way that was
acceptable to the Azure DW instance.
.. change::
:tags: bug, postgresql
:tickets: 5520
Fixed issue where the :class:`_postgresql.ENUM` type would not consult the
schema translate map when emitting a CREATE TYPE or DROP TYPE during the
test to see if the type exists or not. Additionally, repaired an issue
where if the same enum were encountered multiple times in a single DDL
sequence, the "check" query would run repeatedly rather than relying upon a
cached value.
.. change::
:tags: bug, tests
:tickets: 5635
Fixed incompatibilities in the test suite when running against Pytest 6.x.
.. changelog::
:version: 1.3.19
:released: August 17, 2020
.. change::
:tags: usecase, py3k
:tickets: #5357
Added a ``**kw`` argument to the :meth:`.DeclarativeMeta.__init__` method.
This allows a class to support the :pep:`487` metaclass hook
``__init_subclass__``. Pull request courtesy Ewen Gillies.
.. change::
:tags: bug, sql
:tickets: 5470
Repaired an issue where the "ORDER BY" clause rendering a label name rather
than a complete expression, which is particularly important for SQL Server,
would fail to occur if the expression were enclosed in a parenthesized
grouping in some cases. This case has been added to test support. The
change additionally adjusts the "automatically add ORDER BY columns when
DISTINCT is present" behavior of ORM query, deprecated in 1.4, to more
accurately detect column expressions that are already present.
.. change::
:tags: usecase, mysql
:tickets: 5481
The MySQL dialect will render FROM DUAL for a SELECT statement that has no
FROM clause but has a WHERE clause. This allows things like "SELECT 1 WHERE
EXISTS (subquery)" kinds of queries to be used as well as other use cases.
.. change::
:tags: bug, mssql, sql
:tickets: 5467
Fixed bug where the mssql dialect incorrectly escaped object names that
contained ']' character(s).
.. change::
:tags: bug, reflection, sqlite, mssql
:tickets: 5456
Applied a sweep through all included dialects to ensure names that contain
single or double quotes are properly escaped when querying system tables,
for all :class:`.Inspector` methods that accept object names as an argument
(e.g. table names, view names, etc). SQLite and MSSQL contained two
quoting issues that were repaired.
.. change::
:tags: bug, mysql
:tickets: 5411
Fixed an issue where CREATE TABLE statements were not specifying the
COLLATE keyword correctly.
.. change::
:tags: bug, datatypes, sql
:tickets: 4733
The ``LookupError`` message will now provide the user with up to four
possible values that a column is constrained to via the :class:`.Enum`.
Values longer than 11 characters will be truncated and replaced with
ellipses. Pull request courtesy Ramon Williams.
.. change::
:tags: bug, postgresql
:tickets: 5476
Fixed issue where the return type for the various RANGE comparison
operators would itself be the same RANGE type rather than BOOLEAN, which
would cause an undesirable result in the case that a
:class:`.TypeDecorator` that defined result-processing behavior were in
use. Pull request courtesy Jim Bosch.
.. change::
:tags: bug, mysql
:tickets: 5493
Added MariaDB code 1927 to the list of "disconnect" codes, as recent
MariaDB versions apparently use this code when the database server was
stopped.
.. change::
:tags: usecase, declarative, orm
:tickets: 5513
The name of the virtual column used when using the
:class:`_declarative.AbstractConcreteBase` and
:class:`_declarative.ConcreteBase` classes can now be customized, to allow
for models that have a column that is actually named ``type``. Pull
request courtesy Jesse-Bakker.
.. change::
:tags: usecase, orm
:tickets: 5494
Adjusted the workings of the :meth:`_orm.Mapper.all_orm_descriptors`
accessor to represent the attributes in the order that they are located in
a deterministic way, assuming the use of Python 3.6 or higher which
maintains the sorting order of class attributes based on how they were
declared. This sorting is not guaranteed to match the declared order of
attributes in all cases however; see the method documentation for the exact
scheme.
.. change::
:tags: bug, sql
:tickets: 5500
Fixed issue where the
:paramref:`_engine.Connection.execution_options.schema_translate_map`
feature would not take effect when the :meth:`_schema.Sequence.next_value`
function function for a :class:`_schema.Sequence` were used in the
:paramref:`_schema.Column.server_default` parameter and the create table
DDL were emitted.
.. changelog::
:version: 1.3.18
:released: June 25, 2020
.. change::
:tags: bug, sqlite
:tickets: 5395
Added "exists" to the list of reserved words for SQLite so that this word
will be quoted when used as a label or column name. Pull request courtesy
Thodoris Sotiropoulos.
.. change::
:tags: bug, mssql
:tickets: 5366, 5364
Refined the logic used by the SQL Server dialect to interpret multi-part
schema names that contain many dots, to not actually lose any dots if the
name does not have bracking or quoting used, and additionally to support a
"dbname" token that has many parts including that it may have multiple,
independently-bracketed sections.
.. change::
:tags: bug, mssql, pyodbc
:tickets: 5346
Fixed an issue in the pyodbc connector such that a warning about pyodbc
"drivername" would be emitted when using a totally empty URL. Empty URLs
are normal when producing a non-connected dialect object or when using the
"creator" argument to create_engine(). The warning now only emits if the
driver name is missing but other parameters are still present.
.. change::
:tags: bug, mssql
:tickets: 5373
Fixed issue with assembling the ODBC connection string for the pyodbc
DBAPI. Tokens containing semicolons and/or braces "{}" were not being
correctly escaped, causing the ODBC driver to misinterpret the
connection string attributes.
.. change::
:tags: usecase, orm
:tickets: 5326
Improve error message when using :meth:`_query.Query.filter_by` in
a query where the first entity is not a mapped class.
.. change::
:tags: sql, schema
:tickets: 5324
Introduce :class:`.IdentityOptions` to store common parameters for
sequences and identity columns.
.. change::
:tags: usecase, sql
:tickets: 5309
Added a ".schema" parameter to the :func:`_expression.table` construct,
allowing ad-hoc table expressions to also include a schema name.
Pull request courtesy Dylan Modesitt.
.. change::
:tags: bug, mssql
:tickets: 5339
Fixed issue where ``datetime.time`` parameters were being converted to
``datetime.datetime``, making them incompatible with comparisons like
``>=`` against an actual :class:`_mssql.TIME` column.
.. change::
:tags: bug, mssql
:tickets: 5359
Fixed an issue where the ``is_disconnect`` function in the SQL Server
pyodbc dialect was incorrectly reporting the disconnect state when the
exception message had a substring that matched a SQL Server ODBC error
code.
.. change::
:tags: bug, engine
:tickets: 5326
Further refinements to the fixes to the "reset" agent fixed in
:ticket:`5326`, which now emits a warning when it is not being correctly
invoked and corrects for the behavior. Additional scenarios have been
identified and fixed where this warning was being emitted.
.. change::
:tags: usecase, sqlite
:tickets: 5297
SQLite 3.31 added support for computed column. This change
enables their support in SQLAlchemy when targeting SQLite.
.. change::
:tags: bug, schema
:tickets: 5276
Fixed issue where ``dialect_options`` were omitted when a
database object (e.g., :class:`.Table`) was copied using
:func:`.tometadata`.
.. change::
:tags: bug, sql
:tickets: 5344
Correctly apply self_group in type_coerce element.
The type coerce element did not correctly apply grouping rules when using
in an expression
.. change::
:tags: bug, oracle, reflection
:tickets: 5421
Fixed bug in Oracle dialect where indexes that contain the full set of
primary key columns would be mistaken as the primary key index itself,
which is omitted, even if there were multiples. The check has been refined
to compare the name of the primary key constraint against the index name
itself, rather than trying to guess based on the columns present in the
index.
.. change::
:tags: change, sql, sybase
:tickets: 5294
Added ``.offset`` support to sybase dialect.
Pull request courtesy Alan D. Snow.
.. change::
:tags: bug, engine
:tickets: 5341
Fixed issue in :class:`.URL` object where stringifying the object
would not URL encode special characters, preventing the URL from being
re-consumable as a real URL. Pull request courtesy Miguel Grinberg.
.. change::
:tags: usecase, mysql
:tickets: 4860
Implemented row-level locking support for mysql. Pull request courtesy
Quentin Somerville.
.. change::
:tags: change, mssql
:tickets: 5321
Moved the ``supports_sane_rowcount_returning = False`` requirement from
the ``PyODBCConnector`` level to the ``MSDialect_pyodbc`` since pyodbc
does work properly in some circumstances.
.. change::
:tags: change, examples
Added new option ``--raw`` to the examples.performance suite
which will dump the raw profile test for consumption by any
number of profiling visualizer tools. Removed the "runsnake"
option as runsnake is very hard to build at this point;
.. change::
:tags: bug, sql
:tickets: 5353
Added :meth:`.Select.with_hint` output to the generic SQL string that is
produced when calling ``str()`` on a statement. Previously, this clause
would be omitted under the assumption that it was dialect specific.
The hint text is presented within brackets to indicate the rendering
of such hints varies among backends.
.. change::
:tags: usecase, orm
:tickets: 5198
Added a new parameter :paramref:`_orm.query_expression.default_expr` to the
:func:`_orm.query_expression` construct, which will be appled to queries
automatically if the :func:`_orm.with_expression` option is not used. Pull
request courtesy Haoyu Sun.
.. changelog::
:version: 1.3.17
:released: May 13, 2020
.. change::
:tags: bug, oracle
:tickets: 5246
Some modifications to how the cx_oracle dialect sets up per-column
outputtype handlers for LOB and numeric datatypes to adjust for potential
changes coming in cx_Oracle 8.
.. change::
:tags: bug, orm
:tickets: 5288
Fixed bug where using :func:`.with_polymorphic` as the target of a join via
:meth:`.RelationshipComparator.of_type` on a mapper that already has a
subquery-based with_polymorphic setting that's equivalent to the one
requested would not correctly alias the ON clause in the join.
.. change::
:tags: bug, oracle, performance
:tickets: 5314
Changed the implementation of fetching CLOB and BLOB objects to use
cx_Oracle's native implementation which fetches CLOB/BLOB objects inline
with other result columns, rather than performing a separate fetch. As
always, this can be disabled by setting auto_convert_lobs to False.
As part of this change, the behavior of a CLOB that was given a blank
string on INSERT now returns None on SELECT, which is now consistent with
that of VARCHAR on Oracle.
.. change::
:tags: usecase, postgresql
:tickets: 5265
Added support for columns or type :class:`_sqltypes.ARRAY` of :class:`.Enum`,
:class:`_postgresql.JSON` or :class:`_postgresql.JSONB` in PostgreSQL.
Previously a workaround was required in these use cases.
.. change::
:tags: schema
:tickets: 4138
Add ``comment`` attribute to :class:`_schema.Column` ``__repr__`` method.
.. change::
:tags: bug, orm
:tickets: 5303
Fixed issue in the area of where loader options such as selectinload()
interact with the baked query system, such that the caching of a query is
not supposed to occur if the loader options themselves have elements such
as with_polymorphic() objects in them that currently are not
cache-compatible. The baked loader could sometimes not fully invalidate
itself in these some of these scenarios leading to missed eager loads.
.. change::
:tags: bug, engine
:tickets: 5326
Fixed fairly critical issue where the DBAPI connection could be returned to
the connection pool while still in an un-rolled-back state. The reset agent
responsible for rolling back the connection could be corrupted in the case
that the transaction was "closed" without being rolled back or committed,
which can occur in some scenarios when using ORM sessions and emitting
.close() in a certain pattern involving savepoints. The fix ensures that
the reset agent is always active.
.. change::
:tags: bug, orm
:tickets: 5304
Modified the internal "identity set" implementation, which is a set that
hashes objects on their id() rather than their hash values, to not actually
call the ``__hash__()`` method of the objects, which are typically
user-mapped objects. Some methods were calling this method as a side
effect of the implementation.
.. change::
:tags: usecase, postgresql
:tickets: 5266
Raise an explicit :class:`.exc.CompileError` when adding a table with a
column of type :class:`_sqltypes.ARRAY` of :class:`.Enum` configured with
:paramref:`.Enum.native_enum` set to ``False`` when
:paramref:`.Enum.create_constraint` is not set to ``False``
.. change::
:tags: bug, schema
:tickets: 5298
Fixed issue where an :class:`.Index` that is deferred in being associated
with a table, such as as when it contains a :class:`.Column` that is not
associated with any :class:`.Table` yet, would fail to attach correctly if
it also contained a non table-oriented expression.
.. change::
:tags: change, firebird
:tickets: 5278
Adjusted dialect loading for ``firebird://`` URIs so the external
sqlalchemy-firebird dialect will be used if it has been installed,
otherwise fall back to the (now deprecated) internal Firebird dialect.
.. change::
:tags: bug, mssql, reflection
:tickets: 5255
Fix a regression introduced by the reflection of computed column in
MSSQL when using the legacy TDS version 4.2. The dialect will try
to detect the protocol version of first connect and run in compatibility
mode if it cannot detect it.
.. change::
:tags: bug, mssql, reflection
:tickets: 5271
Fix a regression introduced by the reflection of computed column in
MSSQL when using SQL server versions before 2012, which does not support
the ``concat`` function.
.. change::
:tags: bug, orm
:tickets: 5269
An informative error message is raised when an ORM many-to-one comparison
is attempted against an object that is not an actual mapped instance.
Comparisons such as those to scalar subqueries aren't supported;
generalized comparison with subqueries is better achieved using
:meth:`~.RelationshipProperty.Comparator.has`.
.. change::
:tags: usecase, orm
:tickets: 5262
Added an accessor :attr:`.ColumnProperty.Comparator.expressions` which
provides access to the group of columns mapped under a multi-column
:class:`.ColumnProperty` attribute.
.. change::
:tags: bug, schema
:tickets: 5316
A warning is emitted when making use of the :attr:`.MetaData.sorted_tables`
attribute as well as the :func:`_schema.sort_tables` function, and the
given tables cannot be correctly sorted due to a cyclic dependency between
foreign key constraints. In this case, the functions will no longer sort
the involved tables by foreign key, and a warning will be emitted. Other
tables that are not part of the cycle will still be returned in dependency
order. Previously, the sorted_table routines would return a collection that
would unconditionally omit all foreign keys when a cycle was detected, and
no warning was emitted.
.. change::
:tags: orm, usecase
:tickets: 5237
Introduce :paramref:`_orm.relationship.sync_backref` flag in a relationship
to control if the synchronization events that mutate the in-Python
attributes are added. This supersedes the previous change :ticket:`5149`,
which warned that ``viewonly=True`` relationship target of a
back_populates or backref configuration would be disallowed.
.. changelog::
:version: 1.3.16
:released: April 7, 2020
.. change::
:tags: oracle, usecase
:tickets: 5200
Implemented AUTOCOMMIT isolation level for Oracle when using cx_Oracle.
Also added a fixed default isolation level of READ COMMITTED for Oracle.
.. change::
:tags: bug, mysql
:tickets: 5239
Fixed issue in MySQL dialect when connecting to a pseudo-MySQL database
such as that provided by ProxySQL, the up front check for isolation level
when it returns no row will not prevent the dialect from continuing to
connect. A warning is emitted that the isolation level could not be
detected.
.. change::
:tags: bug, tests
:tickets: 5201
Fixed an issue that prevented the test suite from running with the
recently released py.test 5.4.0.
.. change::
:tags: bug, oracle, reflection
:tickets: 5146
Fixed regression / incorrect fix caused by fix for :ticket:`5146` where the
Oracle dialect reads from the "all_tab_comments" view to get table comments
but fails to accommodate for the current owner of the table being
requested, causing it to read the wrong comment if multiple tables of the
same name exist in multiple schemas.
.. change::
:tags: types, enum
:tickets: 5183
The :class:`.Enum` type now supports the parameter :paramref:`.Enum.length`
to specify the length of the VARCHAR column to create when using
non native enums by setting :paramref:`.Enum.native_enum` to ``False``
.. change::
:tags: bug, orm
:tickets: 5228
Fixed bug in :func:`_orm.selectinload` loading option where two or more
loaders that represent different relationships with the same string key
name as referenced from a single :func:`_orm.with_polymorphic` construct
with multiple subclass mappers would fail to invoke each subqueryload
separately, instead making use of a single string-based slot that would
prevent the other loaders from being invoked.
.. change::
:tags: schema, reflection
:tickets: 5063
Added support for reflection of "computed" columns, which are now returned
as part of the structure returned by :meth:`_reflection.Inspector.get_columns`.
When reflecting full :class:`_schema.Table` objects, computed columns will
be represented using the :class:`.Computed` construct.
.. change::
:tags: orm, performance
:tickets: 5162
Modified the queries used by subqueryload and selectinload to no longer
ORDER BY the primary key of the parent entity; this ordering was there to
allow the rows as they come in to be copied into lists directly with a
minimal level of Python-side collation. However, these ORDER BY clauses
can negatively impact the performance of the query as in many scenarios
these columns are derived from a subquery or are otherwise not actual
primary key columns such that SQL planners cannot make use of indexes. The
Python-side collation uses the native itertools.group_by() to collate the
incoming rows, and has been modified to allow multiple
row-groups-per-parent to be assembled together using list.extend(), which
should still allow for relatively fast Python-side performance. There will
still be an ORDER BY present for a relationship that includes an explicit
order_by parameter, however this is the only ORDER BY that will be added to
the query for both kinds of loading.
.. change::
:tags: mssql, mysql, oracle, usecase
:tickets: 5137
Added support for :meth:`.ColumnOperators.is_distinct_from` and
:meth:`.ColumnOperators.isnot_distinct_from` to SQL Server,
MySQL, and Oracle.
.. change::
:tags: sqlite, usecase
:tickets: 5164
Implemented AUTOCOMMIT isolation level for SQLite when using pysqlite.
.. change::
:tags: bug, postgresql
:tickets: 5205
Fixed issue where a "covering" index, e.g. those which have an INCLUDE
clause, would be reflected including all the columns in INCLUDE clause as
regular columns. A warning is now emitted if these additional columns are
detected indicating that they are currently ignored. Note that full
support for "covering" indexes is part of :ticket:`4458`. Pull request
courtesy Marat Sharafutdinov.
.. change::
:tags: sql, types
:tickets: 5052
Add ability to literal compile a :class:`DateTime`, :class:`Date`
or :class:`Time` when using the string dialect for debugging purposes.
This change does not impact real dialect implementation that retain
their current behavior.
.. change::
:tags: installer
:tickets: 5207
Ensured that the "pyproject.toml" file is not included in builds, as the
presence of this file indicates to pip that a pep-517 installation process
should be used. As this mode of operation appears to be not well supported
by current tools / distros, these problems are avoided within the scope
of SQLAlchemy installation by omitting the file.
.. change::
:tags: bug, orm
:tickets: 5210
Fixed issue where a lazyload that uses session-local "get" against a target
many-to-one relationship where an object with the correct primary key is
present, however it's an instance of a sibling class, does not correctly
return None as is the case when the lazy loader actually emits a load for
that row.
.. change::
:tags: bug, orm, declarative
:tickets: 5238
The string argument accepted as the first positional argument by the
:func:`_orm.relationship` function when using the Declarative API is no longer
interpreted using the Python ``eval()`` function; instead, the name is dot
separated and the names are looked up directly in the name resolution
dictionary without treating the value as a Python expression. However,
passing a string argument to the other :func:`_orm.relationship` parameters
that necessarily must accept Python expressions will still use ``eval()``;
the documentation has been clarified to ensure that there is no ambiguity
that this is in use.
.. seealso::
:ref:`declarative_relationship_eval` - details on string evaluation
.. changelog::
:version: 1.3.15
:released: March 11, 2020
.. change::
:tags: bug, orm
:tickets: 5194
Adjusted the error message emitted by :meth:`_query.Query.join` when a left hand
side can't be located that the :meth:`_query.Query.select_from` method is the
best way to resolve the issue. Also, within the 1.3 series, used a
deterministic ordering when determining the FROM clause from a given column
entity passed to :class:`_query.Query` so that the same expression is determined
each time.
.. change::
:tags: orm, bug
:tickets: 5196
Fixed regression in 1.3.14 due to :ticket:`4849` where a sys.exc_info()
call failed to be invoked correctly when a flush error would occur. Test
coverage has been added for this exception case.
.. changelog::
:version: 1.3.14
:released: March 10, 2020
.. change::
:tags: bug, sql, postgresql
:tickets: 5181
Fixed bug where a CTE of an INSERT/UPDATE/DELETE that also uses RETURNING
could then not be SELECTed from directly, as the internal state of the
compiler would try to treat the outer SELECT as a DELETE statement itself
and access nonexistent state.
.. change::
:tags: bug, orm
:tickets: 5110
Fixed regression caused in 1.3.13 by :ticket:`5056` where a refactor of the
ORM path registry system made it such that a path could no longer be
compared to an empty tuple, which can occur in a particular kind of joined
eager loading path. The "empty tuple" use case has been resolved so that
the path registry is compared to a path registry in all cases; the
:class:`.PathRegistry` object itself now implements ``__eq__()`` and
``__ne__()`` methods which will take place for all equality comparisons and
continue to succeed in the not anticipated case that a non-
:class:`.PathRegistry` object is compared, while emitting a warning that
this object should not be the subject of the comparison.
.. change::
:tags: bug, orm
:tickets: 5149
Setting a relationship to viewonly=True which is also the target of a
back_populates or backref configuration will now emit a warning and
eventually be disallowed. back_populates refers specifically to mutation
of an attribute or collection, which is disallowed when the attribute is
subject to viewonly=True. The viewonly attribute is not subject to
persistence behaviors which means it will not reflect correct results
when it is locally mutated.
.. change::
:tags: bug, oracle
:tickets: 5146
Fixed a reflection bug where table comments could only be retrieved for
tables actually owned by the user but not for tables visible to the user
but owned by someone else. Pull request courtesy Dave Hirschfeld.
.. change::
:tags: bug, performance
:tickets: 5180
Revised an internal change to the test system added as a result of
:ticket:`5085` where a testing-related module per dialect would be loaded
unconditionally upon making use of that dialect, pulling in SQLAlchemy's
testing framework as well as the ORM into the module import space. This
would only impact initial startup time and memory to a modest extent,
however it's best that these additional modules aren't reverse-dependent on
straight Core usage.
.. change::
:tags: bug, installation
:tickets: 5138
Vendored the ``inspect.formatannotation`` function inside of
``sqlalchemy.util.compat``, which is needed for the vendored version of
``inspect.formatargspec``. The function is not documented in cPython and
is not guaranteed to be available in future Python versions.
.. change::
:tags: bug, mssql
:tickets: 5132
Fixed issue where the :class:`_mssql.DATETIMEOFFSET` type would not
accommodate for the ``None`` value, introduced as part of the series of
fixes for this type first introduced in :ticket:`4983`, :ticket:`5045`.
Additionally, added support for passing a backend-specific date formatted
string through this type, as is typically allowed for date/time types on
most other DBAPIs.
.. change::
:tags: bug, engine
:tickets: 5182
Expanded the scope of cursor/connection cleanup when a statement is
executed to include when the result object fails to be constructed, or an
after_cursor_execute() event raises an error, or autocommit / autoclose
fails. This allows the DBAPI cursor to be cleaned up on failure and for
connectionless execution allows the connection to be closed out and
returned to the connection pool, where previously it waiting until garbage
collection would trigger a pool return.
.. change::
:tags: bug, postgresql
:tickets: 5158
Fixed issue where the "schema_translate_map" feature would not work with a
PostgreSQL native enumeration type (i.e. :class:`.Enum`,
:class:`_postgresql.ENUM`) in that while the "CREATE TYPE" statement would
be emitted with the correct schema, the schema would not be rendered in
the CREATE TABLE statement at the point at which the enumeration was
referenced.
.. change::
:tags: usecase, ext
:tickets: 5114
Added keyword arguments to the :meth:`.MutableList.sort` function so that a
key function as well as the "reverse" keyword argument can be provided.
.. change::
:tags: bug, general, py3k
:tickets: 4849
Applied an explicit "cause" to most if not all internally raised exceptions
that are raised from within an internal exception catch, to avoid
misleading stacktraces that suggest an error within the handling of an
exception. While it would be preferable to suppress the internally caught
exception in the way that the ``__suppress_context__`` attribute would,
there does not as yet seem to be a way to do this without suppressing an
enclosing user constructed context, so for now it exposes the internally
caught exception as the cause so that full information about the context
of the error is maintained.
.. change::
:tags: orm, bug
:tickets: 5121
Fixed an additional regression in the same area as that of :ticket:`5080`
introduced in 1.3.0b3 via :ticket:`4468` where the ability to create a
joined option across a :func:`.with_polymorphic` into a relationship
against the base class of that with_polymorphic, and then further into
regular mapped relationships would fail as the base class component would
not add itself to the load path in a way that could be located by the
loader strategy. The changes applied in :ticket:`5080` have been further
refined to also accommodate this scenario.
.. change::
:tags: bug, postgresql, reflection
:tickets: 5170
Fixed bug where PostgreSQL reflection of CHECK constraints would fail to
parse the constraint if the SQL text contained newline characters. The
regular expression has been adjusted to accommodate for this case. Pull
request courtesy Eric Borczuk.
.. change::
:tags: usecase, orm
:tickets: 5129
Added a new flag :paramref:`.InstanceEvents.restore_load_context` and
:paramref:`.SessionEvents.restore_load_context` which apply to the
:meth:`.InstanceEvents.load`, :meth:`.InstanceEvents.refresh`, and
:meth:`.SessionEvents.loaded_as_persistent` events, which when set will
restore the "load context" of the object after the event hook has been
called. This ensures that the object remains within the "loader context"
of the load operation that is already ongoing, rather than the object being
transferred to a new load context due to refresh operations which may have
occurred in the event. A warning is now emitted when this condition occurs,
which recommends use of the flag to resolve this case. The flag is
"opt-in" so that there is no risk introduced to existing applications.
The change additionally adds support for the ``raw=True`` flag to
session lifecycle events.
.. change::
:tags: bug, mysql
:tickets: 5173
Fixed issue in MySQL :meth:`.mysql.Insert.on_duplicate_key_update` construct
where using a SQL function or other composed expression for a column argument
would not properly render the ``VALUES`` keyword surrounding the column
itself.
.. changelog::
:version: 1.3.13
:released: January 22, 2020
.. change::
:tags: bug, postgresql
:tickets: 5039
Fixed issue where the PostgreSQL dialect would fail to parse a reflected
CHECK constraint that was a boolean-valued function (as opposed to a
boolean-valued expression).
.. change::
:tags: bug, ext
:tickets: 5086
Fixed bug in sqlalchemy.ext.serializer where a unique
:class:`.BindParameter` object could conflict with itself if it were
present in the mapping itself, as well as the filter condition of the
query, as one side would be used against the non-deserialized version and
the other side would use the deserialized version. Logic is added to
:class:`.BindParameter` similar to its "clone" method which will uniquify
the parameter name upon deserialize so that it doesn't conflict with its
original.
.. change::
:tags: usecase, sql
:tickets: 5079
A function created using :class:`.GenericFunction` can now specify that the
name of the function should be rendered with or without quotes by assigning
the :class:`.quoted_name` construct to the .name element of the object.
Prior to 1.3.4, quoting was never applied to function names, and some
quoting was introduced in :ticket:`4467` but no means to force quoting for
a mixed case name was available. Additionally, the :class:`.quoted_name`
construct when used as the name will properly register its lowercase name
in the function registry so that the name continues to be available via the
``func.`` registry.
.. seealso::
:class:`.GenericFunction`
.. change::
:tags: bug, engine
:tickets: 5048
Fixed issue where the collection of value processors on a
:class:`.Compiled` object would be mutated when "expanding IN" parameters
were used with a datatype that has bind value processors; in particular,
this would mean that when using statement caching and/or baked queries, the
same compiled._bind_processors collection would be mutated concurrently.
Since these processors are the same function for a given bind parameter
namespace every time, there was no actual negative effect of this issue,
however, the execution of a :class:`.Compiled` object should never be
causing any changes in its state, especially given that they are intended
to be thread-safe and reusable once fully constructed.
.. change::
:tags: tests, postgresql
:tickets: 5057
Improved detection of two phase transactions requirement for the PostgreSQL
database by testing that max_prepared_transactions is set to a value
greater than 0. Pull request courtesy Federico Caselli.
.. change::
:tags: bug, orm, engine
:tickets: 5056, 5050, 5071
Added test support and repaired a wide variety of unnecessary reference
cycles created for short-lived objects, mostly in the area of ORM queries.
Thanks much to Carson Ip for the help on this.
.. change::
:tags: orm, bug
:tickets: 5107
Fixed regression in loader options introduced in 1.3.0b3 via :ticket:`4468`
where the ability to create a loader option using
:meth:`.PropComparator.of_type` targeting an aliased entity that is an
inheriting subclass of the entity which the preceding relationship refers
to would fail to produce a matching path. See also :ticket:`5082` fixed
in this same release which involves a similar kind of issue.
.. change::
:tags: bug, tests
:tickets: 4946
Fixed a few test failures which would occur on Windows due to SQLite file
locking issues, as well as some timing issues in connection pool related
tests; pull request courtesy Federico Caselli.
.. change::
:tags: orm, bug
:tickets: 5082
Fixed regression in joined eager loading introduced in 1.3.0b3 via
:ticket:`4468` where the ability to create a joined option across a
:func:`.with_polymorphic` into a polymorphic subclass using
:meth:`.RelationshipProperty.of_type` and then further along regular mapped
relationships would fail as the polymorphic subclass would not add itself
to the load path in a way that could be located by the loader strategy. A
tweak has been made to resolve this scenario.
.. change::
:tags: performance, orm
Identified a performance issue in the system by which a join is constructed
based on a mapped relationship. The clause adaption system would be used
for the majority of join expressions including in the common case where no
adaptation is needed. The conditions under which this adaptation occur
have been refined so that average non-aliased joins along a simple
relationship without a "secondary" table use about 70% less function calls.
.. change::
:tags: usecase, postgresql
:tickets: 5040
Added support for prefixes to the :class:`_expression.CTE` construct, to allow
support for Postgresql 12 "MATERIALIZED" and "NOT MATERIALIZED" phrases.
Pull request courtesy Marat Sharafutdinov.
.. seealso::
:meth:`_expression.HasCTE.cte`
.. change::
:tags: bug, mssql
:tickets: 5045
Fixed issue where a timezone-aware ``datetime`` value being converted to
string for use as a parameter value of a :class:`_mssql.DATETIMEOFFSET`
column was omitting the fractional seconds.
.. change::
:tags: bug, orm
:tickets: 5068
Repaired a warning in the ORM flush process that was not covered by test
coverage when deleting objects that use the "version_id" feature. This
warning is generally unreachable unless using a dialect that sets the
"supports_sane_rowcount" flag to False, which is not typically the case
however is possible for some MySQL configurations as well as older Firebird
drivers, and likely some third party dialects.
.. change::
:tags: bug, orm
:tickets: 5065
Fixed bug where usage of joined eager loading would not properly wrap the
query inside of a subquery when :meth:`_query.Query.group_by` were used against
the query. When any kind of result-limiting approach is used, such as
DISTINCT, LIMIT, OFFSET, joined eager loading embeds the row-limited query
inside of a subquery so that the collection results are not impacted. For
some reason, the presence of GROUP BY was never included in this criterion,
even though it has a similar effect as using DISTINCT. Additionally, the
bug would prevent using GROUP BY at all for a joined eager load query for
most database platforms which forbid non-aggregated, non-grouped columns
from being in the query, as the additional columns for the joined eager
load would not be accepted by the database.
.. changelog::
:version: 1.3.12
:released: December 16, 2019
.. change::
:tags: bug, sql
:tickets: 5028
Fixed bug where "distinct" keyword passed to :func:`_expression.select` would not
treat a string value as a "label reference" in the same way that the
:meth:`_expression.select.distinct` does; it would instead raise unconditionally. This
keyword argument and the others passed to :func:`_expression.select` will ultimately
be deprecated for SQLAlchemy 2.0.
.. change::
:tags: bug, orm
:tickets: 4997
Fixed issue involving ``lazy="raise"`` strategy where an ORM delete of an
object would raise for a simple "use-get" style many-to-one relationship
that had lazy="raise" configured. This is inconsistent vs. the change
introduced in 1.3 as part of :ticket:`4353`, where it was established that
a history operation that does not expect emit SQL should bypass the
``lazy="raise"`` check, and instead effectively treat it as
``lazy="raise_on_sql"`` for this case. The fix adjusts the lazy loader
strategy to not raise for the case where the lazy load was instructed that
it should not emit SQL if the object were not present.
.. change::
:tags: bug, sql
Changed the text of the exception for "Can't resolve label reference" to
include other kinds of label coercions, namely that "DISTINCT" is also in
this category under the PostgreSQL dialect.
.. change::
:tags: bug, orm
:tickets: 5000
Fixed regression introduced in 1.3.0 related to the association proxy
refactor in :ticket:`4351` that prevented :func:`.composite` attributes
from working in terms of an association proxy that references them.
.. change::
:tags: bug, mssql
:tickets: 4983
Repaired support for the :class:`_mssql.DATETIMEOFFSET` datatype on PyODBC,
by adding PyODBC-level result handlers as it does not include native
support for this datatype. This includes usage of the Python 3 "timezone"
tzinfo subclass in order to set up a timezone, which on Python 2 makes
use of a minimal backport of "timezone" in sqlalchemy.util.
.. change::
:tags: bug, orm
:tickets: 4993
Setting persistence-related flags on :func:`_orm.relationship` while also
setting viewonly=True will now emit a regular warning, as these flags do
not make sense for a viewonly=True relationship. In particular, the
"cascade" settings have their own warning that is generated based on the
individual values, such as "delete, delete-orphan", that should not apply
to a viewonly relationship. Note however that in the case of "cascade",
these settings are still erroneously taking effect even though the
relationship is set up as "viewonly". In 1.4, all persistence-related
cascade settings will be disallowed on a viewonly=True relationship in
order to resolve this issue.
.. change::
:tags: bug, sqlite
:tickets: 5014
Fixed issue to workaround SQLite's behavior of assigning "numeric" affinity
to JSON datatypes, first described at :ref:`change_3850`, which returns
scalar numeric JSON values as a number and not as a string that can be JSON
deserialized. The SQLite-specific JSON deserializer now gracefully
degrades for this case as an exception and bypasses deserialization for
single numeric values, as from a JSON perspective they are already
deserialized.
.. change::
:tags: bug, orm, py3k
:tickets: 4990
Fixed issue where when assigning a collection to itself as a slice, the
mutation operation would fail as it would first erase the assigned
collection inadvertently. As an assignment that does not change the
contents should not generate events, the operation is now a no-op. Note
that the fix only applies to Python 3; in Python 2, the ``__setitem__``
hook isn't called in this case; ``__setslice__`` is used instead which
recreates the list item-by-item in all cases.
.. change::
:tags: bug, orm
:tickets: 5034
Fixed issue where by if the "begin" of a transaction failed at the Core
engine/connection level, such as due to network error or database is locked
for some transactional recipes, within the context of the :class:`.Session`
procuring that connection from the connection pool and then immediately
returning it, the ORM :class:`.Session` would not close the connection
despite this connection not being stored within the state of that
:class:`.Session`. This would lead to the connection being cleaned out by
the connection pool weakref handler within garbage collection which is an
unpreferred codepath that in some special configurations can emit errors in
standard error.
.. changelog::
:version: 1.3.11
:released: November 11, 2019
.. change::
:tags: bug, mssql
:tickets: 4973
Fixed issue in MSSQL dialect where an expression-based OFFSET value in a
SELECT would be rejected, even though the dialect can render this
expression inside of a ROW NUMBER-oriented LIMIT/OFFSET construct.
.. change::
:tags: orm, usecase
:tickets: 4934
Added accessor :meth:`_query.Query.is_single_entity` to :class:`_query.Query`, which
will indicate if the results returned by this :class:`_query.Query` will be a
list of ORM entities, or a tuple of entities or column expressions.
SQLAlchemy hopes to improve upon the behavior of single entity / tuples in
future releases such that the behavior would be explicit up front, however
this attribute should be helpful with the current behavior. Pull request
courtesy Patrick Hayes.
.. change::
:tags: bug, mysql
:tickets: 4945
Added "Connection was killed" message interpreted from the base
pymysql.Error class in order to detect closed connection, based on reports
that this message is arriving via a pymysql.InternalError() object which
indicates pymysql is not handling it correctly.
.. change::
:tags: bug, orm
:tickets: 4954
The :paramref:`_orm.relationship.omit_join` flag was not intended to be
manually set to True, and will now emit a warning when this occurs. The
omit_join optimization is detected automatically, and the ``omit_join``
flag was only intended to disable the optimization in the hypothetical case
that the optimization may have interfered with correct results, which has
not been observed with the modern version of this feature. Setting the
flag to True when it is not automatically detected may cause the selectin
load feature to not work correctly when a non-default primary join
condition is in use.
.. change::
:tags: bug, orm
:tickets: 4915
A warning is emitted if a primary key value is passed to :meth:`_query.Query.get`
that consists of None for all primary key column positions. Previously,
passing a single None outside of a tuple would raise a ``TypeError`` and
passing a composite None (tuple of None values) would silently pass
through. The fix now coerces the single None into a tuple where it is
handled consistently with the other None conditions. Thanks to Lev
Izraelit for the help with this.
.. change::
:tags: bug, orm
:tickets: 4947
The :class:`.BakedQuery` will not cache a query that was modified by a
:meth:`.QueryEvents.before_compile` event, so that compilation hooks that
may be applying ad-hoc modifications to queries will take effect on each
run. In particular this is helpful for events that modify queries used in
lazy loading as well as eager loading such as "select in" loading. In
order to re-enable caching for a query modified by this event, a new
flag ``bake_ok`` is added; see :ref:`baked_with_before_compile` for
details.
A longer term plan to provide a new form of SQL caching should solve this
kind of issue more comprehensively.
.. change::
:tags: bug, tests
:tickets: 4920
Fixed test failures which would occur with newer SQLite as of version 3.30
or greater, due to their addition of nulls ordering syntax as well as new
restrictions on aggregate functions. Pull request courtesy Nils Philippsen.
.. change::
:tags: bug, installation, windows
:tickets: 4967
Added a workaround for a setuptools-related failure that has been observed
as occurring on Windows installations, where setuptools is not correctly
reporting a build error when the MSVC build dependencies are not installed
and therefore not allowing graceful degradation into non C extensions
builds.
.. change::
:tags: bug, sql, py3k
:tickets: 4931
Changed the ``repr()`` of the :class:`.quoted_name` construct to use
regular string repr() under Python 3, rather than running it through
"backslashreplace" escaping, which can be misleading.
.. change::
:tags: bug, oracle, firebird
:tickets: 4931
Modified the approach of "name normalization" for the Oracle and Firebird
dialects, which converts from the UPPERCASE-as-case-insensitive convention
of these dialects into lowercase-as-case-insensitive for SQLAlchemy, to not
automatically apply the :class:`.quoted_name` construct to a name that
matches itself under upper or lower case conversion, as is the case for
many non-european characters. All names used within metadata structures
are converted to :class:`.quoted_name` objects in any case; the change
here would only affect the output of some inspection functions.
.. change::
:tags: bug, schema
:tickets: 4911
Fixed bug where a table that would have a column label overlap with a plain
column name, such as "foo.id AS foo_id" vs. "foo.foo_id", would prematurely
generate the ``._label`` attribute for a column before this overlap could
be detected due to the use of the ``index=True`` or ``unique=True`` flag on
the column in conjunction with the default naming convention of
``"column_0_label"``. This would then lead to failures when ``._label``
were used later to generate a bound parameter name, in particular those
used by the ORM when generating the WHERE clause for an UPDATE statement.
The issue has been fixed by using an alternate ``._label`` accessor for DDL
generation that does not affect the state of the :class:`_schema.Column`. The
accessor also bypasses the key-deduplication step as it is not necessary
for DDL, the naming is now consistently ``"<tablename>_<columnname>"``
without any subsequent numeric symbols when used in DDL.
.. change::
:tags: bug, engine
:tickets: 4902
Fixed bug where parameter repr as used in logging and error reporting needs
additional context in order to distinguish between a list of parameters for
a single statement and a list of parameter lists, as the "list of lists"
structure could also indicate a single parameter list where the first
parameter itself is a list, such as for an array parameter. The
engine/connection now passes in an additional boolean indicating how the
parameters should be considered. The only SQLAlchemy backend that expects
arrays as parameters is that of psycopg2 which uses pyformat parameters,
so this issue has not been too apparent, however as other drivers that use
positional gain more features it is important that this be supported. It
also eliminates the need for the parameter repr function to guess based on
the parameter structure passed.
.. change::
:tags: usecase, schema
:tickets: 4894
Added DDL support for "computed columns"; these are DDL column
specifications for columns that have a server-computed value, either upon
SELECT (known as "virtual") or at the point of which they are INSERTed or
UPDATEd (known as "stored"). Support is established for Postgresql, MySQL,
Oracle SQL Server and Firebird. Thanks to Federico Caselli for lots of work
on this one.
.. seealso::
:ref:`computed_ddl`
.. change::
:tags: bug, engine, postgresql
:tickets: 4955
Fixed bug in :class:`_reflection.Inspector` where the cache key generation did not
take into account arguments passed in the form of tuples, such as the tuple
of view name styles to return for the PostgreSQL dialect. This would lead
the inspector to cache too generally for a more specific set of criteria.
The logic has been adjusted to include every keyword element in the cache,
as every argument is expected to be appropriate for a cache else the
caching decorator should be bypassed by the dialect.
.. change::
:tags: bug, mssql
:tickets: 4923
Fixed an issue in the :meth:`_engine.Engine.table_names` method where it would
feed the dialect's default schema name back into the dialect level table
function, which in the case of SQL Server would interpret it as a
dot-tokenized schema name as viewed by the mssql dialect, which would
cause the method to fail in the case where the database username actually
had a dot inside of it. In 1.3, this method is still used by the
:meth:`_schema.MetaData.reflect` function so is a prominent codepath. In 1.4,
which is the current master development branch, this issue doesn't exist,
both because :meth:`_schema.MetaData.reflect` isn't using this method nor does the
method pass the default schema name explicitly. The fix nonetheless
guards against the default server name value returned by the dialect from
being interpreted as dot-tokenized name under any circumstances by
wrapping it in quoted_name().
.. change::
:tags: bug, orm
:tickets: 4974
Fixed ORM bug where a "secondary" table that referred to a selectable which
in some way would refer to the local primary table would apply aliasing to
both sides of the join condition when a relationship-related join, either
via :meth:`_query.Query.join` or by :func:`_orm.joinedload`, were generated. The
"local" side is now excluded.
.. change::
:tags: usecase, sql
:tickets: 4276
Added new accessors to expressions of type :class:`_types.JSON` to allow for
specific datatype access and comparison, covering strings, integers,
numeric, boolean elements. This revises the documented approach of
CASTing to string when comparing values, instead adding specific
functionality into the PostgreSQL, SQlite, MySQL dialects to reliably
deliver these basic types in all cases.
.. seealso::
:class:`_types.JSON`
:meth:`_sqltypes.JSON.Comparator.as_string`
:meth:`_sqltypes.JSON.Comparator.as_boolean`
:meth:`_sqltypes.JSON.Comparator.as_float`
:meth:`_sqltypes.JSON.Comparator.as_integer`
.. change::
:tags: usecase, oracle
:tickets: 4799
Added dialect-level flag ``encoding_errors`` to the cx_Oracle dialect,
which can be specified as part of :func:`_sa.create_engine`. This is passed
to SQLAlchemy's unicode decoding converter under Python 2, and to
cx_Oracle's ``cursor.var()`` object as the ``encodingErrors`` parameter
under Python 3, for the very unusual case that broken encodings are present
in the target database which cannot be fetched unless error handling is
relaxed. The value is ultimately one of the Python "encoding errors"
parameters passed to ``decode()``.
.. change::
:tags: usecase, sql
:tickets: 4933
The :func:`_expression.text` construct now supports "unique" bound parameters, which
will dynamically uniquify themselves on compilation thus allowing multiple
:func:`_expression.text` constructs with the same bound parameter names to be combined
together.
.. change::
:tags: bug, oracle
:tickets: 4913
The :class:`_types.NCHAR` datatype will now bind to the
``cx_Oracle.FIXED_NCHAR`` DBAPI data bindings when used in a bound
parameter, which supplies proper comparison behavior against a
variable-length string. Previously, the :class:`_types.NCHAR` datatype
would bind to ``cx_oracle.NCHAR`` which is not fixed length; the
:class:`_types.CHAR` datatype already binds to ``cx_Oracle.FIXED_CHAR``
so it is now consistent that :class:`_types.NCHAR` binds to
``cx_Oracle.FIXED_NCHAR``.
.. change::
:tags: bug, firebird
:tickets: 4903
Added additional "disconnect" message "Error writing data to the
connection" to Firebird disconnection detection. Pull request courtesy
lukens.
.. changelog::
:version: 1.3.10
:released: October 9, 2019
.. change::
:tags: bug, mssql
:tickets: 4857
Fixed bug in SQL Server dialect with new "max_identifier_length" feature
where the mssql dialect already featured this flag, and the implementation
did not accommodate for the new initialization hook correctly.
.. change::
:tags: bug, oracle
:tickets: 4898, 4857
Fixed regression in Oracle dialect that was inadvertently using max
identifier length of 128 characters on Oracle server 12.2 and greater even
though the stated contract for the remainder of the 1.3 series is that
this value stays at 30 until version SQLAlchemy 1.4. Also repaired issues
with the retrieval of the "compatibility" version, and removed the warning
emitted when the "v$parameter" view was not accessible as this was causing
user confusion.
.. changelog::
:version: 1.3.9
:released: October 4, 2019
.. change::
:tags: usecase, engine
:tickets: 4857
Added new :func:`_sa.create_engine` parameter
:paramref:`_sa.create_engine.max_identifier_length`. This overrides the
dialect-coded "max identifier length" in order to accommodate for databases
that have recently changed this length and the SQLAlchemy dialect has
not yet been adjusted to detect for that version. This parameter interacts
with the existing :paramref:`_sa.create_engine.label_length` parameter in that
it establishes the maximum (and default) value for anonymously generated
labels. Additionally, post-connection detection of max identifier lengths
has been added to the dialect system. This feature is first being used
by the Oracle dialect.
.. seealso::
:ref:`oracle_max_identifier_lengths` - in the Oracle dialect documentation
.. change::
:tags: usecase, oracle
:tickets: 4857
The Oracle dialect now emits a warning if Oracle version 12.2 or greater is
used, and the :paramref:`_sa.create_engine.max_identifier_length` parameter is
not set. The version in this specific case defaults to that of the
"compatibility" version set in the Oracle server configuration, not the
actual server version. In version 1.4, the default max_identifier_length
for 12.2 or greater will move to 128 characters. In order to maintain
forwards compatibility, applications should set
:paramref:`_sa.create_engine.max_identifier_length` to 30 in order to maintain
the same length behavior, or to 128 in order to test the upcoming behavior.
This length determines among other things how generated constraint names
are truncated for statements like ``CREATE CONSTRAINT`` and ``DROP
CONSTRAINT``, which means a the new length may produce a name-mismatch
against a name that was generated with the old length, impacting database
migrations.
.. seealso::
:ref:`oracle_max_identifier_lengths` - in the Oracle dialect documentation
.. change::
:tags: usecase, sqlite
:tickets: 4863
Added support for sqlite "URI" connections, which allow for sqlite-specific
flags to be passed in the query string such as "read only" for Python
sqlite3 drivers that support this.
.. seealso::
:ref:`pysqlite_uri_connections`
.. change::
:tags: bug, tests
:tickets: 4285
Fixed unit test regression released in 1.3.8 that would cause failure for
Oracle, SQL Server and other non-native ENUM platforms due to new
enumeration tests added as part of :ticket:`4285` enum sortability in the
unit of work; the enumerations created constraints that were duplicated on
name.
.. change::
:tags: bug, oracle
:tickets: 4886
Restored adding cx_Oracle.DATETIME to the setinputsizes() call when a
SQLAlchemy :class:`.Date`, :class:`.DateTime` or :class:`.Time` datatype is
used, as some complex queries require this to be present. This was removed
in the 1.2 series for arbitrary reasons.
.. change::
:tags: bug, mssql
:tickets: 4883
Added identifier quoting to the schema name applied to the "use" statement
which is invoked when a SQL Server multipart schema name is used within a
:class:`_schema.Table` that is being reflected, as well as for :class:`_reflection.Inspector`
methods such as :meth:`_reflection.Inspector.get_table_names`; this accommodates for
special characters or spaces in the database name. Additionally, the "use"
statement is not emitted if the current database matches the target owner
database name being passed.
.. change::
:tags: bug, orm
:tickets: 4872
Fixed regression in selectinload loader strategy caused by :ticket:`4775`
(released in version 1.3.6) where a many-to-one attribute of None would no
longer be populated by the loader. While this was usually not noticeable
due to the lazyloader populating None upon get, it would lead to a detached
instance error if the object were detached.
.. change::
:tags: bug, orm
:tickets: 4873
Passing a plain string expression to :meth:`.Session.query` is deprecated,
as all string coercions were removed in :ticket:`4481` and this one should
have been included. The :func:`_expression.literal_column` function may be used to
produce a textual column expression.
.. change::
:tags: usecase, sql
:tickets: 4847
Added an explicit error message for the case when objects passed to
:class:`_schema.Table` are not :class:`.SchemaItem` objects, rather than resolving
to an attribute error.
.. change::
:tags: bug, orm
:tickets: 4890
A warning is emitted for a condition in which the :class:`.Session` may
implicitly swap an object out of the identity map for another one with the
same primary key, detaching the old one, which can be an observed result of
load operations which occur within the :meth:`.SessionEvents.after_flush`
hook. The warning is intended to notify the user that some special
condition has caused this to happen and that the previous object may not be
in the expected state.
.. change::
:tags: bug, sql
:tickets: 4837
Characters that interfere with "pyformat" or "named" formats in bound
parameters, namely ``%, (, )`` and the space character, as well as a few
other typically undesirable characters, are stripped early for a
:func:`.bindparam` that is using an anonymized name, which is typically
generated automatically from a named column which itself includes these
characters in its name and does not use a ``.key``, so that they do not
interfere either with the SQLAlchemy compiler's use of string formatting or
with the driver-level parsing of the parameter, both of which could be
demonstrated before the fix. The change only applies to anonymized
parameter names that are generated and consumed internally, not end-user
defined names, so the change should have no impact on any existing code.
Applies in particular to the psycopg2 driver which does not otherwise quote
special parameter names, but also strips leading underscores to suit Oracle
(but not yet leading numbers, as some anon parameters are currently
entirely numeric/underscore based); Oracle in any case continues to quote
parameter names that include special characters.
.. changelog::
:version: 1.3.8
:released: August 27, 2019
.. change::
:tags: bug, orm
:tickets: 4823
Fixed bug where :class:`_orm.Load` objects were not pickleable due to
mapper/relationship state in the internal context dictionary. These
objects are now converted to picklable using similar techniques as that of
other elements within the loader option system that have long been
serializable.
.. change::
:tags: bug, postgresql
:tickets: 4623
Revised the approach for the just added support for the psycopg2
"execute_values()" feature added in 1.3.7 for :ticket:`4623`. The approach
relied upon a regular expression that would fail to match for a more
complex INSERT statement such as one which had subqueries involved. The
new approach matches exactly the string that was rendered as the VALUES
clause.
.. change::
:tags: usecase, orm
:tickets: 4285
Added support for the use of an :class:`.Enum` datatype using Python
pep-435 enumeration objects as values for use as a primary key column
mapped by the ORM. As these values are not inherently sortable, as
required by the ORM for primary keys, a new
:attr:`.TypeEngine.sort_key_function` attribute is added to the typing
system which allows any SQL type to implement a sorting for Python objects
of its type which is consulted by the unit of work. The :class:`.Enum`
type then defines this using the database value of a given enumeration.
The sorting scheme can be also be redefined by passing a callable to the
:paramref:`.Enum.sort_key_function` parameter. Pull request courtesy
Nicolas Caniart.
.. change::
:tags: bug, engine
:tickets: 4807
Fixed an issue whereby if the dialect "initialize" process which occurs on
first connect would encounter an unexpected exception, the initialize
process would fail to complete and then no longer attempt on subsequent
connection attempts, leaving the dialect in an un-initialized, or partially
initialized state, within the scope of parameters that need to be
established based on inspection of a live connection. The "invoke once"
logic in the event system has been reworked to accommodate for this
occurrence using new, private API features that establish an "exec once"
hook that will continue to allow the initializer to fire off on subsequent
connections, until it completes without raising an exception. This does not
impact the behavior of the existing ``once=True`` flag within the event
system.
.. change::
:tags: bug, sqlite, reflection
:tickets: 4810
Fixed bug where a FOREIGN KEY that was set up to refer to the parent table
by table name only without the column names would not correctly be
reflected as far as setting up the "referred columns", since SQLite's
PRAGMA does not report on these columns if they weren't given explicitly.
For some reason this was hardcoded to assume the name of the local column,
which might work for some cases but is not correct. The new approach
reflects the primary key of the referred table and uses the constraint
columns list as the referred columns list, if the remote column(s) aren't
present in the reflected pragma directly.
.. change::
:tags: bug, postgresql
:tickets: 4822
Fixed bug where Postgresql operators such as
:meth:`.postgresql.ARRAY.Comparator.contains` and
:meth:`.postgresql.ARRAY.Comparator.contained_by` would fail to function
correctly for non-integer values when used against a
:class:`_postgresql.array` object, due to an erroneous assert statement.
.. change::
:tags: feature, engine
:tickets: 4815
Added new parameter :paramref:`_sa.create_engine.hide_parameters` which when
set to True will cause SQL parameters to no longer be logged, nor rendered
in the string representation of a :class:`.StatementError` object.
.. change::
:tags: usecase, postgresql
:tickets: 4824
Added support for reflection of CHECK constraints that include the special
PostgreSQL qualifier "NOT VALID", which can be present for CHECK
constraints that were added to an existing table with the directive that
they not be applied to existing data in the table. The PostgreSQL
dictionary for CHECK constraints as returned by
:meth:`_reflection.Inspector.get_check_constraints` may include an additional entry
``dialect_options`` which within will contain an entry ``"not_valid":
True`` if this symbol is detected. Pull request courtesy Bill Finn.
.. changelog::
:version: 1.3.7
:released: August 14, 2019
.. change::
:tags: bug, sql
:tickets: 4778
Fixed issue where :class:`.Index` object which contained a mixture of
functional expressions which were not resolvable to a particular column,
in combination with string-based column names, would fail to initialize
its internal state correctly leading to failures during DDL compilation.
.. change::
:tags: bug, sqlite
:tickets: 4798
The dialects that support json are supposed to take arguments
``json_serializer`` and ``json_deserializer`` at the create_engine() level,
however the SQLite dialect calls them ``_json_serializer`` and
``_json_deserilalizer``. The names have been corrected, the old names are
accepted with a change warning, and these parameters are now documented as
:paramref:`_sa.create_engine.json_serializer` and
:paramref:`_sa.create_engine.json_deserializer`.
.. change::
:tags: bug, mysql
:tickets: 4804
The MySQL dialects will emit "SET NAMES" at the start of a connection when
charset is given to the MySQL driver, to appease an apparent behavior
observed in MySQL 8.0 that raises a collation error when a UNION includes
string columns unioned against columns of the form CAST(NULL AS CHAR(..)),
which is what SQLAlchemy's polymorphic_union function does. The issue
seems to have affected PyMySQL for at least a year, however has recently
appeared as of mysqlclient 1.4.4 based on changes in how this DBAPI creates
a connection. As the presence of this directive impacts three separate
MySQL charset settings which each have intricate effects based on their
presence, SQLAlchemy will now emit the directive on new connections to
ensure correct behavior.
.. change::
:tags: usecase, postgresql
:tickets: 4623
Added new dialect flag for the psycopg2 dialect, ``executemany_mode`` which
supersedes the previous experimental ``use_batch_mode`` flag.
``executemany_mode`` supports both the "execute batch" and "execute values"
functions provided by psycopg2, the latter which is used for compiled
:func:`_expression.insert` constructs. Pull request courtesy Yuval Dinari.
.. seealso::
:ref:`psycopg2_executemany_mode`
.. change::
:tags: bug, sql
:tickets: 4787
Fixed bug where :meth:`.TypeEngine.column_expression` method would not be
applied to subsequent SELECT statements inside of a UNION or other
:class:`_selectable.CompoundSelect`, even though the SELECT statements are rendered at
the topmost level of the statement. New logic now differentiates between
rendering the column expression, which is needed for all SELECTs in the
list, vs. gathering the returned data type for the result row, which is
needed only for the first SELECT.
.. change::
:tags: bug, sqlite
:tickets: 4793
Fixed bug where usage of "PRAGMA table_info" in SQLite dialect meant that
reflection features to detect for table existence, list of table columns,
and list of foreign keys, would default to any table in any attached
database, when no schema name was given and the table did not exist in the
base schema. The fix explicitly runs PRAGMA for the 'main' schema and then
the 'temp' schema if the 'main' returned no rows, to maintain the behavior
of tables + temp tables in the "no schema" namespace, attached tables only
in the "schema" namespace.
.. change::
:tags: bug, sql
:tickets: 4780
Fixed issue where internal cloning of SELECT constructs could lead to a key
error if the copy of the SELECT changed its state such that its list of
columns changed. This was observed to be occurring in some ORM scenarios
which may be unique to 1.3 and above, so is partially a regression fix.
.. change::
:tags: bug, orm
:tickets: 4777
Fixed regression caused by new selectinload for many-to-one logic where
a primaryjoin condition not based on real foreign keys would cause
KeyError if a related object did not exist for a given key value on the
parent object.
.. change::
:tags: usecase, mysql
:tickets: 4783
Added reserved words ARRAY and MEMBER to the MySQL reserved words list, as
MySQL 8.0 has now made these reserved.
.. change::
:tags: bug, events
:tickets: 4794
Fixed issue in event system where using the ``once=True`` flag with
dynamically generated listener functions would cause event registration of
future events to fail if those listener functions were garbage collected
after they were used, due to an assumption that a listened function is
strongly referenced. The "once" wrapped is now modified to strongly
reference the inner function persistently, and documentation is updated
that using "once" does not imply automatic de-registration of listener
functions.
.. change::
:tags: bug, mysql
:tickets: 4751
Added another fix for an upstream MySQL 8 issue where a case sensitive
table name is reported incorrectly in foreign key constraint reflection,
this is an extension of the fix first added for :ticket:`4344` which
affects a case sensitive column name. The new issue occurs through MySQL
8.0.17, so the general logic of the 88718 fix remains in place.
.. seealso::
https://bugs.mysql.com/bug.php?id=96365 - upstream bug
.. change::
:tags: usecase, mssql
:tickets: 4782
Added new :func:`_mssql.try_cast` construct for SQL Server which emits
"TRY_CAST" syntax. Pull request courtesy Leonel Atencio.
.. change::
:tags: bug, orm
:tickets: 4803
Fixed bug where using :meth:`_query.Query.first` or a slice expression in
conjunction with a query that has an expression based "offset" applied
would raise TypeError, due to an "or" conditional against "offset" that did
not expect it to be a SQL expression as opposed to an integer or None.
.. changelog::
:version: 1.3.6
:released: July 21, 2019
.. change::
:tags: bug, engine
:tickets: 4754
Fixed bug where using reflection function such as :meth:`_schema.MetaData.reflect`
with an :class:`_engine.Engine` object that had execution options applied to it
would fail, as the resulting :class:`.OptionEngine` proxy object failed to
include a ``.engine`` attribute used within the reflection routines.
.. change::
:tags: bug, mysql
:tickets: 4743
Fixed bug where the special logic to render "NULL" for the
:class:`_types.TIMESTAMP` datatype when ``nullable=True`` would not work if the
column's datatype were a :class:`.TypeDecorator` or a :class:`.Variant`.
The logic now ensures that it unwraps down to the original
:class:`_types.TIMESTAMP` so that this special case NULL keyword is correctly
rendered when requested.
.. change::
:tags: performance, orm
:tickets: 4775
The optimization applied to selectin loading in :ticket:`4340` where a JOIN
is not needed to eagerly load related items is now applied to many-to-one
relationships as well, so that only the related table is queried for a
simple join condition. In this case, the related items are queried
based on the value of a foreign key column on the parent; if these columns
are deferred or otherwise not loaded on any of the parent objects in
the collection, the loader falls back to the JOIN method.
.. change::
:tags: bug, orm
:tickets: 4773
Fixed regression caused by :ticket:`4365` where a join from an entity to
itself without using aliases no longer raises an informative error message,
instead failing on an assertion. The informative error condition has been
restored.
.. change::
:tags: orm, feature
:tickets: 4736
Added new loader option method :meth:`_orm.Load.options` which allows loader
options to be constructed hierarchically, so that many sub-options can be
applied to a particular path without needing to call :func:`.defaultload`
many times. Thanks to Alessio Bogon for the idea.
.. change::
:tags: usecase, postgresql
:tickets: 4771
Added support for reflection of indexes on PostgreSQL partitioned tables,
which was added to PostgreSQL as of version 11.
.. change::
:tags: bug, mysql
:tickets: 4624
Enhanced MySQL/MariaDB version string parsing to accommodate for exotic
MariaDB version strings where the "MariaDB" word is embedded among other
alphanumeric characters such as "MariaDBV1". This detection is critical in
order to correctly accommodate for API features that have split between MySQL
and MariaDB such as the "transaction_isolation" system variable.
.. change::
:tags: bug, mssql
:tickets: 4745
Ensured that the queries used to reflect indexes and view definitions will
explicitly CAST string parameters into NVARCHAR, as many SQL Server drivers
frequently treat string values, particularly those with non-ascii
characters or larger string values, as TEXT which often don't compare
correctly against VARCHAR characters in SQL Server's information schema
tables for some reason. These CAST operations already take place for
reflection queries against SQL Server ``information_schema.`` tables but
were missing from three additional queries that are against ``sys.``
tables.
.. change::
:tags: bug, orm
:tickets: 4713
Fixed an issue where the :meth:`.orm._ORMJoin.join` method, which is a
not-internally-used ORM-level method that exposes what is normally an
internal process of :meth:`_query.Query.join`, did not propagate the ``full`` and
``outerjoin`` keyword arguments correctly. Pull request courtesy Denis
Kataev.
.. change::
:tags: bug, sql
:tickets: 4758
Adjusted the initialization for :class:`.Enum` to minimize how often it
invokes the ``.__members__`` attribute of a given PEP-435 enumeration
object, to suit the case where this attribute is expensive to invoke, as is
the case for some popular third party enumeration libraries.
.. change::
:tags: bug, orm
:tickets: 4772
Fixed bug where a many-to-one relationship that specified ``uselist=True``
would fail to update correctly during a primary key change where a related
column needs to change.
.. change::
:tags: bug, orm
:tickets: 4772
Fixed bug where the detection for many-to-one or one-to-one use with a
"dynamic" relationship, which is an invalid configuration, would fail to
raise if the relationship were configured with ``uselist=True``. The
current fix is that it warns, instead of raises, as this would otherwise be
backwards incompatible, however in a future release it will be a raise.
.. change::
:tags: bug, orm
:tickets: 4767
Fixed bug where a synonym created against a mapped attribute that does not
exist yet, as is the case when it refers to backref before mappers are
configured, would raise recursion errors when trying to test for attributes
on it which ultimately don't exist (as occurs when the classes are run
through Sphinx autodoc), as the unconfigured state of the synonym would put
it into an attribute not found loop.
.. change::
:tags: usecase, postgresql
:tickets: 4756
Added support for multidimensional Postgresql array literals via nesting
the :class:`_postgresql.array` object within another one. The
multidimensional array type is detected automatically.
.. seealso::
:class:`_postgresql.array`
.. change::
:tags: bug, sql, postgresql
:tickets: 4760
Fixed issue where the :class:`_functions.array_agg` construct in combination with
:meth:`.FunctionElement.filter` would not produce the correct operator
precedence in combination with the array index operator.
.. change::
:tags: bug, sql
:tickets: 4747
Fixed an unlikely issue where the "corresponding column" routine for unions
and other :class:`_selectable.CompoundSelect` objects could return the wrong column in
some overlapping column situations, thus potentially impacting some ORM
operations when set operations are in use, if the underlying
:func:`_expression.select` constructs were used previously in other similar kinds of
routines, due to a cached value not being cleared.
.. change::
:tags: usecase, sqlite
:tickets: 4766
Added support for composite (tuple) IN operators with SQLite, by rendering
the VALUES keyword for this backend. As other backends such as DB2 are
known to use the same syntax, the syntax is enabled in the base compiler
using a dialect-level flag ``tuple_in_values``. The change also includes
support for "empty IN tuple" expressions for SQLite when using "in_()"
between a tuple value and an empty set.
.. changelog::
:version: 1.3.5
:released: June 17, 2019
.. change::
:tags: bug, mysql
:tickets: 4715
Fixed bug where MySQL ON DUPLICATE KEY UPDATE would not accommodate setting
a column to the value NULL. Pull request courtesy Lukáš Banič.
.. change::
:tags: bug, orm
:tickets: 4723
Fixed a series of related bugs regarding joined table inheritance more than
two levels deep, in conjunction with modification to primary key values,
where those primary key columns are also linked together in a foreign key
relationship as is typical for joined table inheritance. The intermediary
table in a three-level inheritance hierarchy will now get its UPDATE if
only the primary key value has changed and passive_updates=False (e.g.
foreign key constraints not being enforced), whereas before it would be
skipped; similarly, with passive_updates=True (e.g. ON UPDATE CASCADE in
effect), the third-level table will not receive an UPDATE statement as was
the case earlier which would fail since CASCADE already modified it. In a
related issue, a relationship linked to a three-level inheritance hierarchy
on the primary key of an intermediary table of a joined-inheritance
hierarchy will also correctly have its foreign key column updated when the
parent object's primary key is modified, even if that parent object is a
subclass of the linked parent class, whereas before these classes would
not be counted.
.. change::
:tags: bug, orm
:tickets: 4729
Fixed bug where the :attr:`_orm.Mapper.all_orm_descriptors` accessor would
return an entry for the :class:`_orm.Mapper` itself under the declarative
``__mapper__`` key, when this is not a descriptor. The ``.is_attribute``
flag that's present on all :class:`.InspectionAttr` objects is now
consulted, which has also been modified to be ``True`` for an association
proxy, as it was erroneously set to False for this object.
.. change::
:tags: bug, orm
:tickets: 4704
Fixed regression in :meth:`_query.Query.join` where the ``aliased=True`` flag
would not properly apply clause adaptation to filter criteria, if a
previous join were made to the same entity. This is because the adapters
were placed in the wrong order. The order has been reversed so that the
adapter for the most recent ``aliased=True`` call takes precedence as was
the case in 1.2 and earlier. This broke the "elementtree" examples among
other things.
.. change::
:tags: bug, orm, py3k
:tickets: 4674
Replaced the Python compatibility routines for ``getfullargspec()`` with a
fully vendored version from Python 3.3. Originally, Python was emitting
deprecation warnings for this function in Python 3.8 alphas. While this
change was reverted, it was observed that Python 3 implementations for
``getfullargspec()`` are an order of magnitude slower as of the 3.4 series
where it was rewritten against ``Signature``. While Python plans to
improve upon this situation, SQLAlchemy projects for now are using a simple
replacement to avoid any future issues.
.. change::
:tags: bug, orm
:tickets: 4694
Reworked the attribute mechanics used by :class:`.AliasedClass` to no
longer rely upon calling ``__getattribute__`` on the MRO of the wrapped
class, and to instead resolve the attribute normally on the wrapped class
using getattr(), and then unwrap/adapt that. This allows a greater range
of attribute styles on the mapped class including special ``__getattr__()``
schemes; but it also makes the code simpler and more resilient in general.
.. change::
:tags: usecase, postgresql
:tickets: 4717
Added support for column sorting flags when reflecting indexes for
PostgreSQL, including ASC, DESC, NULLSFIRST, NULLSLAST. Also adds this
facility to the reflection system in general which can be applied to other
dialects in future releases. Pull request courtesy Eli Collins.
.. change::
:tags: bug, postgresql
:tickets: 4701
Fixed bug where PostgreSQL dialect could not correctly reflect an ENUM
datatype that has no members, returning a list with ``None`` for the
``get_enums()`` call and raising a TypeError when reflecting a column which
has such a datatype. The inspection now returns an empty list.
.. change::
:tags: bug, sql
:tickets: 4730
Addressed a range of quoting issues originating from the use of the
:func:`_expression.literal_column`` construct. When this construct is
"proxied" through a subquery and referred to by a label matching its
text, the label does not have quoting rules applied to it, even if the
string in the :class:`.Label` was set up using a :class:`.quoted_name``
construct. Not applying quoting to the text of the :class:`.Label` is a
bug because this text is strictly a SQL identifier name and not a SQL
expression, and the string should not have quotes embedded into it
already unlike the :func:`_expression.literal_column` which it may be
applied towards. The existing behavior of a non-labeled
:func:`_expression.literal_column` being propagated as is on the
outside of a subquery is maintained in order to help with manual
quoting schemes, although it's not clear if valid SQL can be generated
for such a construct in any case.
.. changelog::
:version: 1.3.4
:released: May 27, 2019
.. change::
:tags: feature, mssql
:tickets: 4657
Added support for SQL Server filtered indexes, via the ``mssql_where``
parameter which works similarly to that of the ``postgresql_where`` index
function in the PostgreSQL dialect.
.. seealso::
:ref:`mssql_index_where`
.. change::
:tags: bug, misc
:tickets: 4625
Removed errant "sqla_nose.py" symbol from MANIFEST.in which created an
undesirable warning message.
.. change::
:tags: bug, sql
:tickets: 4653
Fixed that the :class:`.GenericFunction` class was inadvertently
registering itself as one of the named functions. Pull request courtesy
Adrien Berchet.
.. change::
:tags: bug, engine, postgresql
:tickets: 4663
Moved the "rollback" which occurs during dialect initialization so that it
occurs after additional dialect-specific initialize steps, in particular
those of the psycopg2 dialect which would inadvertently leave transactional
state on the first new connection, which could interfere with some
psycopg2-specific APIs which require that no transaction is started. Pull
request courtesy Matthew Wilkes.
.. change::
:tags: bug, orm
:tickets: 4695
Fixed issue where the :paramref:`.AttributeEvents.active_history` flag
would not be set for an event listener that propagated to a subclass via the
:paramref:`.AttributeEvents.propagate` flag. This bug has been present
for the full span of the :class:`.AttributeEvents` system.
.. change::
:tags: bug, orm
:tickets: 4690
Fixed regression where new association proxy system was still not proxying
hybrid attributes when they made use of the ``@hybrid_property.expression``
decorator to return an alternate SQL expression, or when the hybrid
returned an arbitrary :class:`.PropComparator`, at the expression level.
This involved further generalization of the heuristics used to detect the
type of object being proxied at the level of :class:`.QueryableAttribute`,
to better detect if the descriptor ultimately serves mapped classes or
column expressions.
.. change::
:tags: bug, orm
:tickets: 4686
Applied the mapper "configure mutex" against the declarative class mapping
process, to guard against the race which can occur if mappers are used
while dynamic module import schemes are still in the process of configuring
mappers for related classes. This does not guard against all possible race
conditions, such as if the concurrent import has not yet encountered the
dependent classes as of yet, however it guards against as much as possible
within the SQLAlchemy declarative process.
.. change::
:tags: bug, mssql
:tickets: 4680
Added error code 20047 to "is_disconnect" for pymssql. Pull request
courtesy Jon Schuff.
.. change::
:tags: bug, postgresql, orm
:tickets: 4661
Fixed an issue where the "number of rows matched" warning would emit even if
the dialect reported "supports_sane_multi_rowcount=False", as is the case
for psycogp2 with ``use_batch_mode=True`` and others.
.. change::
:tags: bug, sql
:tickets: 4618
Fixed issue where double negation of a boolean column wouldn't reset
the "NOT" operator.
.. change::
:tags: mysql, bug
:tickets: 4650
Added support for DROP CHECK constraint which is required by MySQL 8.0.16
to drop a CHECK constraint; MariaDB supports plain DROP CONSTRAINT. The
logic distinguishes between the two syntaxes by checking the server version
string for MariaDB presence. Alembic migrations has already worked
around this issue by implementing its own DROP for MySQL / MariaDB CHECK
constraints, however this change implements it straight in Core so that its
available for general use. Pull request courtesy Hannes Hansen.
.. change::
:tags: bug, orm
:tickets: 4647
A warning is now emitted for the case where a transient object is being
merged into the session with :meth:`.Session.merge` when that object is
already transient in the :class:`.Session`. This warns for the case where
the object would normally be double-inserted.
.. change::
:tags: bug, orm
:tickets: 4676
Fixed regression in new relationship m2o comparison logic first introduced
at :ref:`change_4359` when comparing to an attribute that is persisted as
NULL and is in an un-fetched state in the mapped instance. Since the
attribute has no explicit default, it needs to default to NULL when
accessed in a persistent setting.
.. change::
:tags: bug, sql
:tickets: 4569
The :class:`.GenericFunction` namespace is being migrated so that function
names are looked up in a case-insensitive manner, as SQL functions do not
collide on case sensitive differences nor is this something which would
occur with user-defined functions or stored procedures. Lookups for
functions declared with :class:`.GenericFunction` now use a case
insensitive scheme, however a deprecation case is supported which allows
two or more :class:`.GenericFunction` objects with the same name of
different cases to exist, which will cause case sensitive lookups to occur
for that particular name, while emitting a warning at function registration
time. Thanks to Adrien Berchet for a lot of work on this complicated
feature.
.. changelog::
:version: 1.3.3
:released: April 15, 2019
.. change::
:tags: bug, postgresql
:tickets: 4601
Fixed regression from release 1.3.2 caused by :ticket:`4562` where a URL
that contained only a query string and no hostname, such as for the
purposes of specifying a service file with connection information, would no
longer be propagated to psycopg2 properly. The change in :ticket:`4562`
has been adjusted to further suit psycopg2's exact requirements, which is
that if there are any connection parameters whatsoever, the "dsn" parameter
is no longer required, so in this case the query string parameters are
passed alone.
.. change::
:tags: bug, pool
:tickets: 4585
Fixed behavioral regression as a result of deprecating the "use_threadlocal"
flag for :class:`_pool.Pool`, where the :class:`.SingletonThreadPool` no longer
makes use of this option which causes the "rollback on return" logic to take
place when the same :class:`_engine.Engine` is used multiple times in the context
of a transaction to connect or implicitly execute, thereby cancelling the
transaction. While this is not the recommended way to work with engines
and connections, it is nonetheless a confusing behavioral change as when
using :class:`.SingletonThreadPool`, the transaction should stay open
regardless of what else is done with the same engine in the same thread.
The ``use_threadlocal`` flag remains deprecated however the
:class:`.SingletonThreadPool` now implements its own version of the same
logic.
.. change::
:tags: bug, orm
:tickets: 4584
Fixed 1.3 regression in new "ambiguous FROMs" query logic introduced in
:ref:`change_4365` where a :class:`_query.Query` that explicitly places an entity
in the FROM clause with :meth:`_query.Query.select_from` and also joins to it
using :meth:`_query.Query.join` would later cause an "ambiguous FROM" error if
that entity were used in additional joins, as the entity appears twice in
the "from" list of the :class:`_query.Query`. The fix resolves this ambiguity by
folding the standalone entity into the join that it's already a part of in
the same way that ultimately happens when the SELECT statement is rendered.
.. change::
:tags: bug, ext
:tickets: 4603
Fixed bug where using ``copy.copy()`` or ``copy.deepcopy()`` on
:class:`.MutableList` would cause the items within the list to be
duplicated, due to an inconsistency in how Python pickle and copy both make
use of ``__getstate__()`` and ``__setstate__()`` regarding lists. In order
to resolve, a ``__reduce_ex__`` method had to be added to
:class:`.MutableList`. In order to maintain backwards compatibility with
existing pickles based on ``__getstate__()``, the ``__setstate__()`` method
remains as well; the test suite asserts that pickles made against the old
version of the class can still be deserialized by the pickle module.
.. change::
:tags: bug, orm
:tickets: 4606
Adjusted the :meth:`_query.Query.filter_by` method to not call :func:`.and()`
internally against multiple criteria, instead passing it off to
:meth:`_query.Query.filter` as a series of criteria, instead of a single criteria.
This allows :meth:`_query.Query.filter_by` to defer to :meth:`_query.Query.filter`'s
treatment of variable numbers of clauses, including the case where the list
is empty. In this case, the :class:`_query.Query` object will not have a
``.whereclause``, which allows subsequent "no whereclause" methods like
:meth:`_query.Query.select_from` to behave consistently.
.. change::
:tags: bug, mssql
:tickets: 4587
Fixed issue in SQL Server dialect where if a bound parameter were present in
an ORDER BY expression that would ultimately not be rendered in the SQL
Server version of the statement, the parameters would still be part of the
execution parameters, leading to DBAPI-level errors. Pull request courtesy
Matt Lewellyn.
.. changelog::
:version: 1.3.2
:released: April 2, 2019
.. change::
:tags: bug, documentation, sql
:tickets: 4580
Thanks to :ref:`change_3981`, we no longer need to rely on recipes that
subclass dialect-specific types directly, :class:`.TypeDecorator` can now
handle all cases. Additionally, the above change made it slightly less
likely that a direct subclass of a base SQLAlchemy type would work as
expected, which could be misleading. Documentation has been updated to use
:class:`.TypeDecorator` for these examples including the PostgreSQL
"ArrayOfEnum" example datatype and direct support for the "subclass a type
directly" has been removed.
.. change::
:tags: bug, postgresql
:tickets: 4550
Modified the :paramref:`.Select.with_for_update.of` parameter so that if a
join or other composed selectable is passed, the individual :class:`_schema.Table`
objects will be filtered from it, allowing one to pass a join() object to
the parameter, as occurs normally when using joined table inheritance with
the ORM. Pull request courtesy Raymond Lu.
.. change::
:tags: feature, postgresql
:tickets: 4562
Added support for parameter-less connection URLs for the psycopg2 dialect,
meaning, the URL can be passed to :func:`_sa.create_engine` as
``"postgresql+psycopg2://"`` with no additional arguments to indicate an
empty DSN passed to libpq, which indicates to connect to "localhost" with
no username, password, or database given. Pull request courtesy Julian
Mehnle.
.. change::
:tags: bug, orm, ext
:tickets: 4574, 4573
Restored instance-level support for plain Python descriptors, e.g.
``@property`` objects, in conjunction with association proxies, in that if
the proxied object is not within ORM scope at all, it gets classified as
"ambiguous" but is proxed directly. For class level access, a basic class
level``__get__()`` now returns the
:class:`.AmbiguousAssociationProxyInstance` directly, rather than raising
its exception, which is the closest approximation to the previous behavior
that returned the :class:`.AssociationProxy` itself that's possible. Also
improved the stringification of these objects to be more descriptive of
current state.
.. change::
:tags: bug, orm
:tickets: 4537
Fixed bug where use of :func:`.with_polymorphic` or other aliased construct
would not properly adapt when the aliased target were used as the
:meth:`_expression.Select.correlate_except` target of a subquery used inside of a
:func:`.column_property`. This required a fix to the clause adaption
mechanics to properly handle a selectable that shows up in the "correlate
except" list, in a similar manner as which occurs for selectables that show
up in the "correlate" list. This is ultimately a fairly fundamental bug
that has lasted for a long time but it is hard to come across it.
.. change::
:tags: bug, orm
:tickets: 4566
Fixed regression where a new error message that was supposed to raise when
attempting to link a relationship option to an AliasedClass without using
:meth:`.PropComparator.of_type` would instead raise an ``AttributeError``.
Note that in 1.3, it is no longer valid to create an option path from a
plain mapper relationship to an :class:`.AliasedClass` without using
:meth:`.PropComparator.of_type`.
.. changelog::
:version: 1.3.1
:released: March 9, 2019
.. change::
:tags: bug, mssql
:tickets: 4525
Fixed regression in SQL Server reflection due to :ticket:`4393` where the
removal of open-ended ``**kw`` from the :class:`.Float` datatype caused
reflection of this type to fail due to a "scale" argument being passed.
.. change::
:tags: bug, orm, ext
:tickets: 4522
Fixed regression where an association proxy linked to a synonym would no
longer work, both at instance level and at class level.
.. changelog::
:version: 1.3.0
:released: March 4, 2019
.. change::
:tags: feature, schema
:tickets: 4517
Added new parameters :paramref:`_schema.Table.resolve_fks` and
:paramref:`.MetaData.reflect.resolve_fks` which when set to False will
disable the automatic reflection of related tables encountered in
:class:`_schema.ForeignKey` objects, which can both reduce SQL overhead for omitted
tables as well as avoid tables that can't be reflected for database-specific
reasons. Two :class:`_schema.Table` objects present in the same :class:`_schema.MetaData`
collection can still refer to each other even if the reflection of the two
tables occurred separately.
.. change::
:tags: feature, orm
:tickets: 4316
The :meth:`_query.Query.get` method can now accept a dictionary of attribute keys
and values as a means of indicating the primary key value to load; is
particularly useful for composite primary keys. Pull request courtesy
Sanjana S.
.. change::
:tags: feature, orm
:tickets: 3133
A SQL expression can now be assigned to a primary key attribute for an ORM
flush in the same manner as ordinary attributes as described in
:ref:`flush_embedded_sql_expressions` where the expression will be evaluated
and then returned to the ORM using RETURNING, or in the case of pysqlite,
works using the cursor.lastrowid attribute.Requires either a database that
supports RETURNING (e.g. Postgresql, Oracle, SQL Server) or pysqlite.
.. change::
:tags: bug, sql
:tickets: 4509
The :class:`_expression.Alias` class and related subclasses :class:`_expression.CTE`,
:class:`_expression.Lateral` and :class:`_expression.TableSample` have been reworked so that it is
not possible for a user to construct the objects directly. These constructs
require that the standalone construction function or selectable-bound method
be used to instantiate new objects.
.. change::
:tags: feature, engine
:tickets: 4500
Revised the formatting for :class:`.StatementError` when stringified. Each
error detail is broken up over multiple newlines instead of spaced out on a
single line. Additionally, the SQL representation now stringifies the SQL
statement rather than using ``repr()``, so that newlines are rendered as is.
Pull request courtesy Nate Clark.
.. seealso::
:ref:`change_4500`
.. changelog::
:version: 1.3.0b3
:released: March 4, 2019
:released: February 8, 2019
.. change::
:tags: bug, ext
:tickets: 2642
Implemented a more comprehensive assignment operation (e.g. "bulk replace")
when using association proxy with sets or dictionaries. Fixes the problem
of redundant proxy objects being created to replace the old ones, which
leads to excessive events and SQL and in the case of unique constraints
will cause the flush to fail.
.. seealso::
:ref:`change_2642`
.. change::
:tags: bug, postgresql
:tickets: 4473
Fixed issue where using an uppercase name for an index type (e.g. GIST,
BTREE, etc. ) or an EXCLUDE constraint would treat it as an identifier to
be quoted, rather than rendering it as is. The new behavior converts these
types to lowercase and ensures they contain only valid SQL characters.
.. change::
:tags: bug, orm
:tickets: 4469
Improved the behavior of :func:`_orm.with_polymorphic` in conjunction with
loader options, in particular wildcard operations as well as
:func:`_orm.load_only`. The polymorphic object will be more accurately
targeted so that column-level options on the entity will correctly take
effect.The issue is a continuation of the same kinds of things fixed in
:ticket:`4468`.
.. change::
:tags: bug, sql
:tickets: 4481
Fully removed the behavior of strings passed directly as components of a
:func:`_expression.select` or :class:`_query.Query` object being coerced to :func:`_expression.text`
constructs automatically; the warning that has been emitted is now an
ArgumentError or in the case of order_by() / group_by() a CompileError.
This has emitted a warning since version 1.0 however its presence continues
to create concerns for the potential of mis-use of this behavior.
Note that public CVEs have been posted for order_by() / group_by() which
are resolved by this commit: CVE-2019-7164 CVE-2019-7548
.. seealso::
:ref:`change_4481`
.. change::
:tags: bug, sql
:tickets: 4467
Quoting is applied to :class:`.Function` names, those which are usually but
not necessarily generated from the :attr:`_expression.func` construct, at compile
time if they contain illegal characters, such as spaces or punctuation. The
names are as before treated as case insensitive however, meaning if the
names contain uppercase or mixed case characters, that alone does not
trigger quoting. The case insensitivity is currently maintained for
backwards compatibility.
.. change::
:tags: bug, sql
:tickets: 4481
Added "SQL phrase validation" to key DDL phrases that are accepted as plain
strings, including :paramref:`_schema.ForeignKeyConstraint.on_delete`,
:paramref:`_schema.ForeignKeyConstraint.on_update`,
:paramref:`.ExcludeConstraint.using`,
:paramref:`_schema.ForeignKeyConstraint.initially`, for areas where a series of SQL
keywords only are expected.Any non-space characters that suggest the phrase
would need to be quoted will raise a :class:`.CompileError`. This change
is related to the series of changes committed as part of :ticket:`4481`.
.. change::
:tags: bug, orm, declarative
:tickets: 4470
Added some helper exceptions that invoke when a mapping based on
:class:`.AbstractConcreteBase`, :class:`.DeferredReflection`, or
:class:`.AutoMap` is used before the mapping is ready to be used, which
contain descriptive information on the class, rather than falling through
into other failure modes that are less informative.
.. change::
:tags: change, tests
:tickets: 4460
The test system has removed support for Nose, which is unmaintained for
several years and is producing warnings under Python 3. The test suite is
currently standardized on Pytest. Pull request courtesy Parth Shandilya.
.. changelog::
:version: 1.3.0b2
:released: March 4, 2019
:released: January 25, 2019
.. change::
:tags: bug, ext
:tickets: 4401
Fixed a regression in 1.3.0b1 caused by :ticket:`3423` where association
proxy objects that access an attribute that's only present on a polymorphic
subclass would raise an ``AttributeError`` even though the actual instance
being accessed was an instance of that subclass.
.. change::
:tags: bug, orm
:tickets: 1103
Fixed long-standing issue where duplicate collection members would cause a
backref to delete the association between the member and its parent object
when one of the duplicates were removed, as occurs as a side effect of
swapping two objects in one statement.
.. seealso::
:ref:`change_1103`
.. change::
:tags: bug, mssql
:tickets: 4442
The ``literal_processor`` for the :class:`.Unicode` and
:class:`.UnicodeText` datatypes now render an ``N`` character in front of
the literal string expression as required by SQL Server for Unicode string
values rendered in SQL expressions.
.. change::
:tags: feature, orm
:tickets: 4423
Implemented a new feature whereby the :class:`.AliasedClass` construct can
now be used as the target of a :func:`_orm.relationship`. This allows the
concept of "non primary mappers" to no longer be necessary, as the
:class:`.AliasedClass` is much easier to configure and automatically inherits
all the relationships of the mapped class, as well as preserves the
ability for loader options to work normally.
.. seealso::
:ref:`change_4423`
.. change::
:tags: bug, orm
:tickets: 4373
Extended the fix first made as part of :ticket:`3287`, where a loader option
made against a subclass using a wildcard would extend itself to include
application of the wildcard to attributes on the super classes as well, to a
"bound" loader option as well, e.g. in an expression like
``Load(SomeSubClass).load_only('foo')``. Columns that are part of the
parent class of ``SomeSubClass`` will also be excluded in the same way as if
the unbound option ``load_only('foo')`` were used.
.. change::
:tags: bug, orm
:tickets: 4433
Improved error messages emitted by the ORM in the area of loader option
traversal. This includes early detection of mis-matched loader strategies
along with a clearer explanation why these strategies don't match.
.. change::
:tags: change, orm
:tickets: 4412
Added a new function :func:`_orm.close_all_sessions` which takes
over the task of the :meth:`.Session.close_all` method, which
is now deprecated as this is confusing as a classmethod.
Pull request courtesy Augustin Trancart.
.. change::
:tags: feature, orm
:tickets: 4397
Added new :meth:`.MapperEvents.before_mapper_configured` event. This
event complements the other "configure" stage mapper events with a per
mapper event that receives each :class:`_orm.Mapper` right before its
configure step, and additionally may be used to prevent or delay the
configuration of specific :class:`_orm.Mapper` objects using a new
return value :attr:`.orm.interfaces.EXT_SKIP`. See the
documentation link for an example.
.. seealso::
:meth:`.MapperEvents.before_mapper_configured`
.. change::
:tags: bug, orm
The "remove" event for collections is now called before the item is removed
in the case of the ``collection.remove()`` method, as is consistent with the
behavior for most other forms of collection item removal (such as
``__delitem__``, replacement under ``__setitem__``). For ``pop()`` methods,
the remove event still fires after the operation.
.. change::
:tags: bug, orm declarative
:tickets: 4372
Added a ``__clause_element__()`` method to :class:`.ColumnProperty` which
can allow the usage of a not-fully-declared column or deferred attribute in
a declarative mapped class slightly more friendly when it's used in a
constraint or other column-oriented scenario within the class declaration,
though this still can't work in open-ended expressions; prefer to call the
:attr:`.ColumnProperty.expression` attribute if receiving ``TypeError``.
.. change::
:tags: bug, orm, engine
:tickets: 4464
Added accessors for execution options to Core and ORM, via
:meth:`_query.Query.get_execution_options`,
:meth:`_engine.Connection.get_execution_options`,
:meth:`_engine.Engine.get_execution_options`, and
:meth:`.Executable.get_execution_options`. PR courtesy Daniel Lister.
.. change::
:tags: bug, orm
:tickets: 4446
Fixed issue in association proxy due to :ticket:`3423` which caused the use
of custom :class:`.PropComparator` objects with hybrid attributes, such as
the one demonstrated in the ``dictlike-polymorphic`` example to not
function within an association proxy. The strictness that was added in
:ticket:`3423` has been relaxed, and additional logic to accommodate for
an association proxy that links to a custom hybrid have been added.
.. change::
:tags: change, general
:tickets: 4393
A large change throughout the library has ensured that all objects,
parameters, and behaviors which have been noted as deprecated or legacy now
emit ``DeprecationWarning`` warnings when invoked.As the Python 3
interpreter now defaults to displaying deprecation warnings, as well as that
modern test suites based on tools like tox and pytest tend to display
deprecation warnings, this change should make it easier to note what API
features are obsolete. A major rationale for this change is so that long-
deprecated features that nonetheless still see continue to see real world
use can finally be removed in the near future; the biggest example of this
are the :class:`.SessionExtension` and :class:`.MapperExtension` classes as
well as a handful of other pre-event extension hooks, which have been
deprecated since version 0.7 but still remain in the library. Another is
that several major longstanding behaviors are to be deprecated as well,
including the threadlocal engine strategy, the convert_unicode flag, and non
primary mappers.
.. seealso::
:ref:`change_4393_general`
.. change::
:tags: change, engine
:tickets: 4393
The "threadlocal" engine strategy which has been a legacy feature of
SQLAlchemy since around version 0.2 is now deprecated, along with the
:paramref:`_pool.Pool.threadlocal` parameter of :class:`_pool.Pool` which has no
effect in most modern use cases.
.. seealso::
:ref:`change_4393_threadlocal`
.. change::
:tags: change, sql
:tickets: 4393
The :paramref:`_sa.create_engine.convert_unicode` and
:paramref:`.String.convert_unicode` parameters have been deprecated. These
parameters were built back when most Python DBAPIs had little to no support
for Python Unicode objects, and SQLAlchemy needed to take on the very
complex task of marshalling data and SQL strings between Unicode and
bytestrings throughout the system in a performant way. Thanks to Python 3,
DBAPIs were compelled to adapt to Unicode-aware APIs and today all DBAPIs
supported by SQLAlchemy support Unicode natively, including on Python 2,
allowing this long-lived and very complicated feature to finally be (mostly)
removed. There are still of course a few Python 2 edge cases where
SQLAlchemy has to deal with Unicode however these are handled automatically;
in modern use, there should be no need for end-user interaction with these
flags.
.. seealso::
:ref:`change_4393_convertunicode`
.. change::
:tags: bug, orm
:tickets: 3777
Implemented the ``.get_history()`` method, which also implies availability
of :attr:`.AttributeState.history`, for :func:`.synonym` attributes.
Previously, trying to access attribute history via a synonym would raise an
``AttributeError``.
.. change::
:tags: feature, engine
:tickets: 3689
Added public accessor :meth:`.QueuePool.timeout` that returns the configured
timeout for a :class:`.QueuePool` object. Pull request courtesy Irina Delamare.
.. change::
:tags: feature, sql
:tickets: 4386
Amended the :class:`.AnsiFunction` class, the base of common SQL
functions like ``CURRENT_TIMESTAMP``, to accept positional arguments
like a regular ad-hoc function. This to suit the case that many of
these functions on specific backends accept arguments such as
"fractional seconds" precision and such. If the function is created
with arguments, it renders the parenthesis and the arguments. If
no arguments are present, the compiler generates the non-parenthesized form.
.. changelog::
:version: 1.3.0b1
:released: March 4, 2019
:released: November 16, 2018
.. change::
:tags: bug, ext
:tickets: 3423
Reworked :class:`.AssociationProxy` to store state that's specific to a
parent class in a separate object, so that a single
:class:`.AssociationProxy` can serve for multiple parent classes, as is
intrinsic to inheritance, without any ambiguity in the state returned by it.
A new method :meth:`.AssociationProxy.for_class` is added to allow
inspection of class-specific state.
.. seealso::
:ref:`change_3423`
.. change::
:tags: bug, oracle
:tickets: 4369
Updated the parameters that can be sent to the cx_Oracle DBAPI to both allow
for all current parameters as well as for future parameters not added yet.
In addition, removed unused parameters that were deprecated in version 1.2,
and additionally we are now defaulting "threaded" to False.
.. seealso::
:ref:`change_4369`
.. change::
:tags: bug, oracle
:tickets: 4242
The Oracle dialect will no longer use the NCHAR/NCLOB datatypes
represent generic unicode strings or clob fields in conjunction with
:class:`.Unicode` and :class:`.UnicodeText` unless the flag
``use_nchar_for_unicode=True`` is passed to :func:`_sa.create_engine` -
this includes CREATE TABLE behavior as well as ``setinputsizes()`` for
bound parameters. On the read side, automatic Unicode conversion under
Python 2 has been added to CHAR/VARCHAR/CLOB result rows, to match the
behavior of cx_Oracle under Python 3. In order to mitigate the performance
hit under Python 2, SQLAlchemy's very performant (when C extensions
are built) native Unicode handlers are used under Python 2.
.. seealso::
:ref:`change_4242`
.. change::
:tags: bug, orm
:tickets: 3844
Fixed issue regarding passive_deletes="all", where the foreign key
attribute of an object is maintained with its value even after the object
is removed from its parent collection. Previously, the unit of work would
set this to NULL even though passive_deletes indicated it should not be
modified.
.. seealso::
:ref:`change_3844`
.. change::
:tags: bug, ext
:tickets: 4268
The long-standing behavior of the association proxy collection maintaining
only a weak reference to the parent object is reverted; the proxy will now
maintain a strong reference to the parent for as long as the proxy
collection itself is also in memory, eliminating the "stale association
proxy" error. This change is being made on an experimental basis to see if
any use cases arise where it causes side effects.
.. seealso::
:ref:`change_4268`
.. change::
:tags: bug, sql
:tickets: 4302
Added "like" based operators as "comparison" operators, including
:meth:`.ColumnOperators.startswith` :meth:`.ColumnOperators.endswith`
:meth:`.ColumnOperators.ilike` :meth:`.ColumnOperators.notilike` among many
others, so that all of these operators can be the basis for an ORM
"primaryjoin" condition.
.. change::
:tags: feature, sqlite
:tickets: 3850
Added support for SQLite's json functionality via the new
SQLite implementation for :class:`_types.JSON`, :class:`_sqlite.JSON`.
The name used for the type is ``JSON``, following an example found at
SQLite's own documentation. Pull request courtesy Ilja Everilä.
.. seealso::
:ref:`change_3850`
.. change::
:tags: feature, engine
Added new "lifo" mode to :class:`.QueuePool`, typically enabled by setting
the flag :paramref:`_sa.create_engine.pool_use_lifo` to True. "lifo" mode
means the same connection just checked in will be the first to be checked
out again, allowing excess connections to be cleaned up from the server
side during periods of the pool being only partially utilized. Pull request
courtesy Taem Park.
.. seealso::
:ref:`change_pr467`
.. change::
:tags: bug, orm
:tickets: 4359
Improved the behavior of a relationship-bound many-to-one object expression
such that the retrieval of column values on the related object are now
resilient against the object being detached from its parent
:class:`.Session`, even if the attribute has been expired. New features
within the :class:`.InstanceState` are used to memoize the last known value
of a particular column attribute before its expired, so that the expression
can still evaluate when the object is detached and expired at the same
time. Error conditions are also improved using modern attribute state
features to produce more specific messages as needed.
.. seealso::
:ref:`change_4359`
.. change::
:tags: feature, mysql
:tickets: 4219
Support added for the "WITH PARSER" syntax of CREATE FULLTEXT INDEX
in MySQL, using the ``mysql_with_parser`` keyword argument. Reflection
is also supported, which accommodates MySQL's special comment format
for reporting on this option as well. Additionally, the "FULLTEXT" and
"SPATIAL" index prefixes are now reflected back into the ``mysql_prefix``
index option.
.. change::
:tags: bug, orm, mysql, postgresql
:tickets: 4246
The ORM now doubles the "FOR UPDATE" clause within the subquery that
renders in conjunction with joined eager loading in some cases, as it has
been observed that MySQL does not lock the rows from a subquery. This
means the query renders with two FOR UPDATE clauses; note that on some
backends such as Oracle, FOR UPDATE clauses on subqueries are silently
ignored since they are unnecessary. Additionally, in the case of the "OF"
clause used primarily with PostgreSQL, the FOR UPDATE is rendered only on
the inner subquery when this is used so that the selectable can be targeted
to the table within the SELECT statement.
.. seealso::
:ref:`change_4246`
.. change::
:tags: feature, mssql
:tickets: 4158
Added ``fast_executemany=True`` parameter to the SQL Server pyodbc dialect,
which enables use of pyodbc's new performance feature of the same name
when using Microsoft ODBC drivers.
.. seealso::
:ref:`change_4158`
.. change::
:tags: bug, ext
:tickets: 4308
Fixed multiple issues regarding de-association of scalar objects with the
association proxy. ``del`` now works, and additionally a new flag
:paramref:`.AssociationProxy.cascade_scalar_deletes` is added, which when
set to True indicates that setting a scalar attribute to ``None`` or
deleting via ``del`` will also set the source association to ``None``.
.. seealso::
:ref:`change_4308`
.. change::
:tags: feature, ext
:tickets: 4318
Added new feature :meth:`.BakedQuery.to_query`, which allows for a
clean way of using one :class:`.BakedQuery` as a subquery inside of another
:class:`.BakedQuery` without needing to refer explicitly to a
:class:`.Session`.
.. change::
:tags: feature, sqlite
:tickets: 4360
Implemented the SQLite ``ON CONFLICT`` clause as understood at the DDL
level, e.g. for primary key, unique, and CHECK constraints as well as
specified on a :class:`_schema.Column` to satisfy inline primary key and NOT NULL.
Pull request courtesy Denis Kataev.
.. seealso::
:ref:`change_4360`
.. change::
:tags: feature, postgresql
:tickets: 4237
Added rudimental support for reflection of PostgreSQL
partitioned tables, e.g. that relkind='p' is added to reflection
queries that return table information.
.. seealso::
:ref:`change_4237`
.. change::
:tags: feature, ext
:tickets: 4351
The :class:`.AssociationProxy` now has standard column comparison operations
such as :meth:`.ColumnOperators.like` and
:meth:`.ColumnOperators.startswith` available when the target attribute is a
plain column - the EXISTS expression that joins to the target table is
rendered as usual, but the column expression is then use within the WHERE
criteria of the EXISTS. Note that this alters the behavior of the
``.contains()`` method on the association proxy to make use of
:meth:`.ColumnOperators.contains` when used on a column-based attribute.
.. seealso::
:ref:`change_4351`
.. change::
:tags: feature, orm
Added new flag :paramref:`.Session.bulk_save_objects.preserve_order` to the
:meth:`.Session.bulk_save_objects` method, which defaults to True. When set
to False, the given mappings will be grouped into inserts and updates per
each object type, to allow for greater opportunities to batch common
operations together. Pull request courtesy Alessandro Cucci.
.. change::
:tags: bug, orm
:tickets: 4365
Refactored :meth:`_query.Query.join` to further clarify the individual components
of structuring the join. This refactor adds the ability for
:meth:`_query.Query.join` to determine the most appropriate "left" side of the
join when there is more than one element in the FROM list or the query is
against multiple entities. If more than one FROM/entity matches, an error
is raised that asks for an ON clause to be specified to resolve the
ambiguity. In particular this targets the regression we saw in
:ticket:`4363` but is also of general use. The codepaths within
:meth:`_query.Query.join` are now easier to follow and the error cases are
decided more specifically at an earlier point in the operation.
.. seealso::
:ref:`change_4365`
.. change::
:tags: bug, sql
:tickets: 3981
Fixed issue with :meth:`.TypeEngine.bind_expression` and
:meth:`.TypeEngine.column_expression` methods where these methods would not
work if the target type were part of a :class:`.Variant`, or other target
type of a :class:`.TypeDecorator`. Additionally, the SQL compiler now
calls upon the dialect-level implementation when it renders these methods
so that dialects can now provide for SQL-level processing for built-in
types.
.. seealso::
:ref:`change_3981`
.. change::
:tags: bug, orm
:tickets: 4304
Fixed long-standing issue in :class:`_query.Query` where a scalar subquery such
as produced by :meth:`_query.Query.exists`, :meth:`_query.Query.as_scalar` and other
derivations from :attr:`_query.Query.statement` would not correctly be adapted
when used in a new :class:`_query.Query` that required entity adaptation, such as
when the query were turned into a union, or a from_self(), etc. The change
removes the "no adaptation" annotation from the :func:`_expression.select` object
produced by the :attr:`_query.Query.statement` accessor.
.. change::
:tags: bug, orm, declarative
:tickets: 4133
Fixed bug where declarative would not update the state of the
:class:`_orm.Mapper` as far as what attributes were present, when additional
attributes were added or removed after the mapper attribute collections had
already been called and memoized. Additionally, a ``NotImplementedError``
is now raised if a fully mapped attribute (e.g. column, relationship, etc.)
is deleted from a class that is currently mapped, since the mapper will not
function correctly if the attribute has been removed.
.. change::
:tags: bug, mssql
:tickets: 4362
Deprecated the use of :class:`.Sequence` with SQL Server in order to affect
the "start" and "increment" of the IDENTITY value, in favor of new
parameters ``mssql_identity_start`` and ``mssql_identity_increment`` which
set these parameters directly. :class:`.Sequence` will be used to generate
real ``CREATE SEQUENCE`` DDL with SQL Server in a future release.
.. seealso::
:ref:`change_4362`
.. change::
:tags: feature, mysql
Added support for the parameters in an ON DUPLICATE KEY UPDATE statement on
MySQL to be ordered, since parameter order in a MySQL UPDATE clause is
significant, in a similar manner as that described at
:ref:`tutorial_parameter_ordered_updates`. Pull request courtesy Maxim Bublis.
.. seealso::
:ref:`change_mysql_ondupordering`
.. change::
:tags: feature, sql
:tickets: 4144
Added :class:`.Sequence` to the "string SQL" system that will render a
meaningful string expression (``"<next sequence value: my_sequence>"``)
when stringifying without a dialect a statement that includes a "sequence
nextvalue" expression, rather than raising a compilation error.
.. change::
:tags: bug, orm
:tickets: 4232
An informative exception is re-raised when a primary key value is not
sortable in Python during an ORM flush under Python 3, such as an ``Enum``
that has no ``__lt__()`` method; normally Python 3 raises a ``TypeError``
in this case. The flush process sorts persistent objects by primary key
in Python so the values must be sortable.
.. change::
:tags: orm, bug
:tickets: 3604
Removed the collection converter used by the :class:`.MappedCollection`
class. This converter was used only to assert that the incoming dictionary
keys matched that of their corresponding objects, and only during a bulk set
operation. The converter can interfere with a custom validator or
:meth:`.AttributeEvents.bulk_replace` listener that wants to convert
incoming values further. The ``TypeError`` which would be raised by this
converter when an incoming key didn't match the value is removed; incoming
values during a bulk assignment will be keyed to their value-generated key,
and not the key that's explicitly present in the dictionary.
Overall, @converter is superseded by the
:meth:`.AttributeEvents.bulk_replace` event handler added as part of
:ticket:`3896`.
.. change::
:tags: feature, sql
:tickets: 3989
Added new naming convention tokens ``column_0N_name``, ``column_0_N_name``,
etc., which will render the names / keys / labels for all columns referenced
by a particular constraint in a sequence. In order to accommodate for the
length of such a naming convention, the SQL compiler's auto-truncation
feature now applies itself to constraint names as well, which creates a
shortened, deterministically generated name for the constraint that will
apply to a target backend without going over the character limit of that
backend.
The change also repairs two other issues. One is that the ``column_0_key``
token wasn't available even though this token was documented, the other was
that the ``referred_column_0_name`` token would inadvertently render the
``.key`` and not the ``.name`` of the column if these two values were
different.
.. seealso::
:ref:`change_3989`
.. change::
:tags: feature, ext
:tickets: 4196
Added support for bulk :meth:`_query.Query.update` and :meth:`_query.Query.delete`
to the :class:`.ShardedQuery` class within the horizontal sharding
extension. This also adds an additional expansion hook to the
bulk update/delete methods :meth:`_query.Query._execute_crud`.
.. seealso::
:ref:`change_4196`
.. change::
:tags: feature, sql
:tickets: 4271
Added new logic to the "expanding IN" bound parameter feature whereby if
the given list is empty, a special "empty set" expression that is specific
to different backends is generated, thus allowing IN expressions to be
fully dynamic including empty IN expressions.
.. seealso::
:ref:`change_4271`
.. change::
:tags: feature, mysql
The "pre-ping" feature of the connection pool now uses
the ``ping()`` method of the DBAPI connection in the case of
mysqlclient, PyMySQL and mysql-connector-python. Pull request
courtesy Maxim Bublis.
.. seealso::
:ref:`change_mysql_ping`
.. change::
:tags: feature, orm
:tickets: 4340
The "selectin" loader strategy now omits the JOIN in the case of a simple
one-to-many load, where it instead relies loads only from the related
table, relying upon the foreign key columns of the related table in order
to match up to primary keys in the parent table. This optimization can be
disabled by setting the :paramref:`_orm.relationship.omit_join` flag to False.
Many thanks to Jayson Reis for the efforts on this.
.. seealso::
:ref:`change_4340`
.. change::
:tags: bug, orm
:tickets: 4353
Added new behavior to the lazy load that takes place when the "old" value of
a many-to-one is retrieved, such that exceptions which would be raised due
to either ``lazy="raise"`` or a detached session error are skipped.
.. seealso::
:ref:`change_4353`
.. change::
:tags: feature, sql
The Python builtin ``dir()`` is now supported for a SQLAlchemy "properties"
object, such as that of a Core columns collection (e.g. ``.c``),
``mapper.attrs``, etc. Allows iPython autocompletion to work as well.
Pull request courtesy Uwe Korn.
.. change::
:tags: feature, orm
:tickets: 4257
Added ``.info`` dictionary to the :class:`.InstanceState` class, the object
that comes from calling :func:`_sa.inspect` on a mapped object.
.. seealso::
:ref:`change_4257`
.. change::
:tags: feature, sql
:tickets: 3831
Added new feature :meth:`.FunctionElement.as_comparison` which allows a SQL
function to act as a binary comparison operation that can work within the
ORM.
.. seealso::
:ref:`change_3831`
.. change::
:tags: bug, orm
:tickets: 4354
A long-standing oversight in the ORM, the ``__delete__`` method for a many-
to-one relationship was non-functional, e.g. for an operation such as ``del
a.b``. This is now implemented and is equivalent to setting the attribute
to ``None``.
.. seealso::
:ref:`change_4354`