MySqlDialect Class — drizzle-orm Architecture

Source Code

drizzle-orm/src/mysql-core/dialect.ts lines 44–1169

export class MySqlDialect {
	static readonly [entityKind]: string = 'MySqlDialect';

	/** @internal */
	readonly casing: CasingCache;

	constructor(config?: MySqlDialectConfig) {
		this.casing = new CasingCache(config?.casing);
	}

	async migrate(
		migrations: MigrationMeta[],
		session: MySqlSession,
		config: Omit<MigrationConfig, 'migrationsSchema'>,
	): Promise<void> {
		const migrationsTable = config.migrationsTable ?? '__drizzle_migrations';
		const migrationTableCreate = sql`
			create table if not exists ${sql.identifier(migrationsTable)} (
				id serial primary key,
				hash text not null,
				created_at bigint
			)
		`;
		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(migrationsTable)} order by created_at desc limit 1`,
		);

		const lastDbMigration = dbMigrations[0];

		await session.transaction(async (tx) => {
			for (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 ${
							sql.identifier(migrationsTable)
						} (\`hash\`, \`created_at\`) values(${migration.hash}, ${migration.folderMillis})`,
					);
				}
			}
		});
	}

	escapeName(name: string): string {
		return `\`${name}\``;
	}

	escapeParam(_num: number): string {
		return `?`;
	}

	escapeString(str: string): string {
		return `'${str.replace(/'/g, "''")}'`;
	}

	private buildWithCTE(queries: Subquery[] | undefined): SQL | undefined {
		if (!queries?.length) return undefined;

		const withSqlChunks = [sql`with `];
		for (const [i, w] of queries.entries()) {
			withSqlChunks.push(sql`${sql.identifier(w._.alias)} as (${w._.sql})`);
			if (i < queries.length - 1) {
				withSqlChunks.push(sql`, `);
			}
		}
		withSqlChunks.push(sql` `);
		return sql.join(withSqlChunks);
	}

	buildDeleteQuery({ table, where, returning, withList, limit, orderBy }: MySqlDeleteConfig): SQL {
		const withSql = this.buildWithCTE(withList);

		const returningSql = returning
			? sql` returning ${this.buildSelection(returning, { isSingleTable: true })}`