Node.js 7如何使用async/await进行sequelize事务？

Question

Node.js 7已经支持async/await语法，在sequelize事务中如果使用async/await会导致事务未启用，应该如何使用？

Answer 1

let transaction;  

try { 
    // get transaction 
    transaction = await sequelize.transaction(); 

    // step 1 
    await Model.destroy({where: {id}, transaction}); 

    // step 2 
    await Model.create({}, {transaction}); 

    // commit 
    await transaction.commit(); 

} catch (err) { 
    // Rollback transaction if any errors were encountered 
    await transaction.rollback(); 
} 

Answer 2

上述代码在销毁调用中有错误。

await Model.destroy({where: {id}, transaction}); 

交易是选项对象的一部分。

Answer 3

通过user7403683给出的答案描述异步/ AWAIT方式对非托管交易（http://docs.sequelizejs.com/manual/tutorial/transactions.html#unmanaged-transaction-then-callback-）

管理的事务在异步/等待风格可能会是这样：

await sequelize.transaction(async t=>{ 
    const user = User.create({ name: "Alex", pwd: "2dwe3dcd" }, { transaction: t}) 
    const group = Group.findOne({ name: "Admins", transaction: t}) 
    // etc. 
}) 

如果发生错误，交易自动回滚。

Answer 4

接受的答案是一个“非托管交易”，它要求您明确地呼叫commit和rollback。谁想要一个“管理交易”，这是它会是什么样子：

try { 
    // Result is whatever you returned inside the transaction 
    let result = await sequelize.transaction(async (transaction) => { 
     // step 1 
     await Model.destroy({where: {id}, transaction}); 

     // step 2 
     return await Model.create({}, {transaction}); 
    }); 

    // In this case, an instance of Model 
    console.log(result); 
} catch (err) { 
    // Rollback transaction if any errors were encountered 
    console.log(err); 
} 

要回滚，只是抛出一个错误的事务函数内：

try { 
    // Result is whatever you returned inside the transaction 
    let result = await sequelize.transaction(async (transaction) => { 
     // step 1 
     await Model.destroy({where: {id}, transaction}); 

     // Cause rollback 
     if(false){ 
      throw new Error('Rollback initiated'); 
     } 

     // step 2 
     return await Model.create({}, {transaction}); 
    }); 

    // In this case, an instance of Model 
    console.log(result); 
} catch (err) { 
    // Rollback transaction if any errors were encountered 
    console.log(err); 
}