migrate() — drizzle-orm Function Reference

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

Function typescript DrizzleORM QueryBuilders

Entity Profile

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

Dependency Diagram

graph TD
  9d69b281_d3a0_656e_aaff_c860c44923b5["migrate()"]
  4ebd26a8_695e_2fdb_c669_8356e302a4ce["migrator.ts"]
  9d69b281_d3a0_656e_aaff_c860c44923b5 -->|defined in| 4ebd26a8_695e_2fdb_c669_8356e302a4ce
  style 9d69b281_d3a0_656e_aaff_c860c44923b5 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

drizzle-orm/src/neon-http/migrator.ts lines 14–59

export async function migrate<TSchema extends Record<string, unknown>>(
	db: NeonHttpDatabase<TSchema>,
	config: MigrationConfig,
) {
	const migrations = readMigrationFiles(config);
	const migrationsTable = config.migrationsTable ?? '__drizzle_migrations';
	const migrationsSchema = 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 db.session.execute(sql`CREATE SCHEMA IF NOT EXISTS ${sql.identifier(migrationsSchema)}`);
	await db.session.execute(migrationTableCreate);

	const dbMigrations = await db.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];
	const rowsToInsert: SQL[] = [];
	for await (const migration of migrations) {
		if (
			!lastDbMigration
			|| Number(lastDbMigration.created_at) < migration.folderMillis
		) {
			for (const stmt of migration.sql) {
				await db.session.execute(sql.raw(stmt));
			}

			rowsToInsert.push(
				sql`insert into ${sql.identifier(migrationsSchema)}.${
					sql.identifier(migrationsTable)
				} ("hash", "created_at") values(${migration.hash}, ${migration.folderMillis})`,
			);
		}
	}

	for await (const rowToInsert of rowsToInsert) {
		await db.session.execute(rowToInsert);
	}
}