Binary-CodeSystemHierarchy-notes.md

This will result in a "code_system_hierarchy" table that looks like this:

id	parent_code	code
1	vehicle	car
1	vehicle	truck
1	vehicle	motorbike
1	car	sedan
1	car	suv
1	car	hatchback
1	truck	pickup
1	truck	semi
{:.table-data}

Given a CodeSystem with nested concepts like:

• vehicle
  • car
    • sedan
    • suv
    • hatchback
  • truck
    • pickup
    • semi
  • motorbike

The repeat directive walks down the concept tree, and at each level the nested forEach extracts each child concept. This produces parent-child pairs that can be used to build adjacency lists for hierarchical queries or to analyse the structure of a terminology.