update-pipeline

Update Pipeline

Converts tracked entity changes into database INSERT/UPDATE/DELETE commands during SaveChanges().

Flow

SaveChanges() → DetectChanges() → IDatabase.SaveChanges() → UpdateAdapter creates IUpdateEntry list → CommandBatchPreparer.BatchCommands() → ModificationCommand per table row, composed of ColumnModification per column → SharedTableEntryMap is used to track entries mapped to the same row → Topological sort via Multigraph (FK dependency ordering) → Groups into ModificationCommandBatch (respects max batch size) → UpdateSqlGenerator generates SQL per batch → BatchExecutor executes all batches in a transaction → StateManager.AcceptAllChanges()

Concurrency

Concurrency tokens → WHERE conditions on UPDATE/DELETE. AffectedCountModificationCommandBatch checks affected rows. Throws DbUpdateConcurrencyException on mismatch.

Shared-Row Value Access

Column accessors may need values from a SharedIdentityEntry when one CLR entry replaces another mapped to the same row. Select the effective entry before resolving the column's property mapping: entries in a shared-identity pair can have different entity types, so a property from the original type must not be used against the replacement. Regression tests should exercise the resulting command dependency ordering, not just the accessor in isolation.

Validation

• SaveChanges() returns expected affected row count
• Store-generated values propagate back to entities after INSERT/UPDATE
• DbUpdateConcurrencyException thrown when expected for stale data