事务

SQL 事务是与数据库交互的一个或多个 SQL 语句的分组。整个事务可以作为单个逻辑单元提交到数据库，也可以作为单个逻辑单元回滚（撤消）。

Drizzle ORM 提供了在事务中运行 SQL 语句的 API：

const db = drizzle(...)

await db.transaction(async (tx) => {
  await tx.update(accounts).set({ balance: sql`${accounts.balance} - 100.00` }).where(eq(users.name, 'Dan'));
  await tx.update(accounts).set({ balance: sql`${accounts.balance} + 100.00` }).where(eq(users.name, 'Andrew'));
});

Drizzle ORM 支持带有嵌套事务 API 的 savepoints：

const db = drizzle(...)

await db.transaction(async (tx) => {
  await tx.update(accounts).set({ balance: sql`${accounts.balance} - 100.00` }).where(eq(users.name, 'Dan'));
  await tx.update(accounts).set({ balance: sql`${accounts.balance} + 100.00` }).where(eq(users.name, 'Andrew'));

  await tx.transaction(async (tx2) => {
    await tx2.update(users).set({ name: "Mr. Dan" }).where(eq(users.name, "Dan"));
  });
});

你可以将业务逻辑嵌入到事务中，并在需要时回滚：

const db = drizzle(...)

await db.transaction(async (tx) => {
  const [account] = await tx.select({ balance: accounts.balance }).from(accounts).where(eq(users.name, 'Dan'));
  if (account.balance < 100) {
    // This throws an exception that rollbacks the transaction.
    tx.rollback()
  }

  await tx.update(accounts).set({ balance: sql`${accounts.balance} - 100.00` }).where(eq(users.name, 'Dan'));
  await tx.update(accounts).set({ balance: sql`${accounts.balance} + 100.00` }).where(eq(users.name, 'Andrew'));
});

你可以从事务中返回值：

const db = drizzle(...)

const newBalance: number = await db.transaction(async (tx) => {
  await tx.update(accounts).set({ balance: sql`${accounts.balance} - 100.00` }).where(eq(users.name, 'Dan'));
  await tx.update(accounts).set({ balance: sql`${accounts.balance} + 100.00` }).where(eq(users.name, 'Andrew'));

  const [account] = await tx.select({ balance: accounts.balance }).from(accounts).where(eq(users.name, 'Dan'));
  return account.balance;
});

你可以将事务与 关系查询 一起使用：

const db = drizzle({ schema })

await db.transaction(async (tx) => {
  await tx.query.users.findMany({
    with: {
      accounts: true
    }
  });
});

我们提供特定于方言的事务配置 API：

PostgreSQL
MySQL
SQLite
SingleStore 
await db.transaction(
  async (tx) => {
    await tx.update(accounts).set({ balance: sql`${accounts.balance} - 100.00` }).where(eq(users.name, "Dan"));
    await tx.update(accounts).set({ balance: sql`${accounts.balance} + 100.00` }).where(eq(users.name, "Andrew"));
  }, {
    isolationLevel: "read committed",
    accessMode: "read write",
    deferrable: true,
  }
);

interface PgTransactionConfig {
  isolationLevel?:
    | "read uncommitted"
    | "read committed"
    | "repeatable read"
    | "serializable";
  accessMode?: "read only" | "read write";
  deferrable?: boolean;
}