perf(query-compiler): add m2m pruning support helpers

Signed-off-by: Alexey Orlenko's AI Agent <robot@aqrln.net>

Author: tensordreams

query-compiler/core/src/query_graph_builder/error.rs

@@ -334,7 +334,6 @@ impl From<DataOperation> for String {
 #[serde(into = "String")]
 pub(crate) enum DependentOperation {
     NestedUpdate,
-    DisconnectRecords,
     FindRecords { model: String },
     InlineRelation { model: String },
     UpdateInlinedRelation { model: String },
@@ -347,10 +346,6 @@ impl DependentOperation {
         Self::NestedUpdate
     }
 
-    pub fn disconnect_records() -> Self {
-        Self::DisconnectRecords
-    }
-
     pub fn find_records(model: &Model) -> Self {
         Self::FindRecords {
             model: model.name().to_owned(),
@@ -386,7 +381,6 @@ impl fmt::Display for DependentOperation {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Self::NestedUpdate => write!(f, "perform a nested update"),
-            Self::DisconnectRecords => write!(f, "disconnect existing child records"),
             Self::FindRecords { model } => write!(f, "find '{model}' record(s)"),
             Self::InlineRelation { model } => write!(f, "inline the relation on '{model}' record(s)"),
             Self::UpdateInlinedRelation { model } => {

query-compiler/core/src/query_graph_builder/write/nested/set_nested.rs

@@ -2,8 +2,7 @@ use super::*;
 use crate::{
     ParsedInputValue,
     inputs::{
-        DisconnectChildrenInput, DisconnectParentInput, IfInput, LeftSideDiffInput, RightSideDiffInput,
-        UpdateManyRecordsSelectorsInput, UpdateOrCreateArgsInput,
+        IfInput, LeftSideDiffInput, RightSideDiffInput, UpdateManyRecordsSelectorsInput, UpdateOrCreateArgsInput,
     },
     query_graph::*,
 };

query-compiler/query-structure/src/model.rs

@@ -20,6 +20,17 @@ impl Model {
             .into()
     }
 
+    pub fn single_primary_identifier_scalar(&self) -> Option<ScalarFieldRef> {
+        let mut ids = self.primary_identifier_scalars();
+        let id = ids.next()?;
+
+        if ids.next().is_some() {
+            return None;
+        }
+
+        Some(self.dm.clone().zip(ScalarFieldId::InModel(id)))
+    }
+
     fn primary_identifier_scalars(&self) -> impl Iterator<Item = psl::parser_database::ScalarFieldId> + use<'_> {
         match self.walker().required_unique_criterias().next() {
             Some(unique) => Either::Left(unique.fields().map(|f| {