Migrations

Pipeline

Add migration: MigrationsScaffolder.ScaffoldMigration() → MigrationsModelDiffer.GetDifferences() → list of MigrationOperation → CSharpMigrationsGenerator and CSharpSnapshotGenerator produce Up/Down/Snapshot code

Apply migration: Migrator.MigrateAsync() → reads __EFMigrationsHistory → per pending: MigrationsSqlGenerator.Generate(operations) → MigrationCommandExecutor executes

Model Snapshot

• Model snapshots use typeof(Dictionary<string, object>) (property bag format), not the actual CLR type. When examining the ClrType in a snapshot, don't assume it matches the real entity type.
• SnapshotModelProcessor.Process() is used at design-time to fixup older model snapshots for backward compatibility.

Testing

Migration operation tests: test/EFCore.Relational.Tests/Migrations/. Functional tests: test/EFCore.{Provider}.FunctionalTests/Migrations/. Model differ tests: test/EFCore.Relational.Tests/Migrations/Internal/MigrationsModelDifferTest*.cs.