Get the reference for ADVANCED schema features the templates do not show — read this before adding authorization or derived fields to a schema. Covers: policy (relationship-based read/write authorization with single- and multi-hop membership paths, and the rules that decide whether adopting it is safe — it replaces creator-ownership per table and fails closed on a null link), computed columns (read-only values derived from other columns), constraints (composite uniqueness, checked at commit when deferrable), audit (append-only audit log), admin_write (a table only admins write), how user foreign keys are attributed on create, reading many rows in one request with __in=a,b,c (the values separated by commas only), deleting the rows a filter names with expected_count, and writes that state the row_version they read (If-Match on a route, if_version in a batch).