| name | change-tracking |
| description | Implementation details for EF Core change tracking. Use when changing InternalEntityEntry, ChangeDetector, SnapshotFactoryFactory, or related entity state, snapshot, or property accessor code. |
| user-invocable | false |
Change Tracking
Manages entity states and detects changes for SaveChanges().
Core Components
StateManager — central engine, identity maps, tracks all entitiesInternalEntityEntry — per-entity state, property flags, snapshotsSnapshotFactoryFactory subclasses build snapshot factories for change detectionPropertyAccessorsFactory, ClrPropertyGetterFactory and ClrPropertySetterFactory compile property accessors for efficient snapshotting and change detection
- Ordinals in
indices parameter specify element at each complex collection depth
Testing
Unit tests: test/EFCore.Tests/ChangeTracking/. Functional tests: test/EFCore.Specification.Tests/GraphUpdates/.
Common Pitfalls
| Pitfall | Solution |
|---|
| There is a failure when there is shared identity entry (Added and Deleted) | Add code that checks SharedIdentityEntry |
Validation
DetectChanges() identifies modified properties via snapshot comparison- Setting original values marks properties as modified or unchanged based on comparison with current values
