migration library

Reviewed, engine-specific Dart migrations and transactional application.

Classes

Migration: A reviewed migration saved as Dart source, independent of application types.
MigrationHistory: Ordered static registration of immutable migrations for one engine.
MigrationPlan: SQL for a reviewed schema transition on one database engine.
MigrationRunner: Applies a static migration history through the database's owned transaction.

freezeSnapshot(SchemaSnapshot snapshot) → SchemaSnapshot: Copies and validates a snapshot without retaining mutable application data.
migrationFingerprint({required int version, required String name, required Engine engine, required List<String> steps, required SchemaSnapshot snapshot}) → String: Calculates the fingerprint to paste into a reviewed Dart migration file.
planSchemaChange(SchemaSnapshot before, SchemaSnapshot after) → MigrationPlan: Plans conservative additions between two complete frozen snapshots.