migrations

Implementation details for EF Core migrations. Use when changing MigrationsSqlGenerator, model diffing, migration operations, HistoryRepository, the Migrator or related classes.

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Migrations

Name: migrations
Rating: 80 (1 reviews)
Author: dotnet

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.

Repository: dotnet/efcore
Path: .agents/skills/migrations/SKILL.md
Commit: 61317c9

Last updated: 5 days ago
First committed: 4 months ago

Also appears in

dotnet/dotnet

In sync

since Jul 28, 2026

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