migrate() — drizzle-orm Function Reference

Architecture documentation for the migrate() function in dialect.ts from the drizzle-orm codebase.

Function typescript DrizzleORM DatabaseDrivers

Entity Profile

DrizzleORM→ DatabaseDrivers→ migrate() — drizzle-orm Function Reference

Dependency Diagram

graph TD
  278c5ac7_639f_2cd1_f288_b7a7db4b7800["migrate()"]
  3977a3fd_2f08_73b1_4df4_3d0fd1858514["PgDialect"]
  278c5ac7_639f_2cd1_f288_b7a7db4b7800 -->|defined in| 3977a3fd_2f08_73b1_4df4_3d0fd1858514
  style 278c5ac7_639f_2cd1_f288_b7a7db4b7800 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

drizzle-orm/src/pg-core/dialect.ts lines 73–112

	async migrate(migrations: MigrationMeta[], session: PgSession, config: string | MigrationConfig): Promise<void> {
		const migrationsTable = typeof config === 'string'
			? '__drizzle_migrations'
			: config.migrationsTable ?? '__drizzle_migrations';
		const migrationsSchema = typeof config === 'string' ? 'drizzle' : config.migrationsSchema ?? 'drizzle';
		const migrationTableCreate = sql`
			CREATE TABLE IF NOT EXISTS ${sql.identifier(migrationsSchema)}.${sql.identifier(migrationsTable)} (
				id SERIAL PRIMARY KEY,
				hash text NOT NULL,
				created_at bigint
			)
		`;
		await session.execute(sql`CREATE SCHEMA IF NOT EXISTS ${sql.identifier(migrationsSchema)}`);
		await session.execute(migrationTableCreate);

		const dbMigrations = await session.all<{ id: number; hash: string; created_at: string }>(
			sql`select id, hash, created_at from ${sql.identifier(migrationsSchema)}.${
				sql.identifier(migrationsTable)
			} order by created_at desc limit 1`,
		);

		const lastDbMigration = dbMigrations[0];
		await session.transaction(async (tx) => {
			for await (const migration of migrations) {
				if (
					!lastDbMigration
					|| Number(lastDbMigration.created_at) < migration.folderMillis
				) {
					for (const stmt of migration.sql) {
						await tx.execute(sql.raw(stmt));
					}
					await tx.execute(
						sql`insert into ${sql.identifier(migrationsSchema)}.${
							sql.identifier(migrationsTable)
						} ("hash", "created_at") values(${migration.hash}, ${migration.folderMillis})`,
					);
				}
			}
		});
	}