对于处理 Sequelize 的方法的调用，这看起来很典型吗？

Question

当我使用有效的AccountNo_Lender 运行它时，数据库更新正常。如果我如上所示通过 null ，我希望看到单行错误error has occurred 但我在块引用中得到了下面显示的内容。这里可能会发生什么？

console.js

const contracts = require('./service');

let contractToUpdate = {
    idContract: 102,
    AccountNo_Lender: null
};

(async () => {

    var results2 = await contracts.update(contractToUpdate);
    console.log(results2);
})();

service.js

require('dotenv/config');
const Sequelize = require('sequelize');

const sequelize = new Sequelize(process.env.DATABASE, process.env.USER, process.env.PASSWORD, {
    host: process.env.HOST,
    dialect: 'mysql',
    operatorsAliases: false,

    pool: {
        max: 5,
        min: 0,
        acquire: 30000,
        idle: 10000
    }

}, {
        define: {
            timestamps: false,
            freezeTableName: true
        }
    });

sequelize
    .authenticate()
    .then(() => {
        console.log('Connection has been established successfully.');
    })
    .catch(err => {
        console.error('Unable to connect to the database:', err);
    });

/**
 * Model for the contract entity.
 */
const Contract = sequelize.define('Contract', {
    idContract: {
        type: Sequelize.INTEGER,
        primaryKey: true
    },
    AccountNo_Lender: {
        type: Sequelize.STRING,
        allowNull: false
    }
});


    
    exports.update = function (contract) {
        return new Promise(function (resolve, reject) {
            Contract.insertOrUpdate(contract)
                .then(c => {
                    resolve(c);
                }).catch(err => {
                    reject('error has occurred.');
                });
        });
    };

被拒绝的承诺

C:\code\mypgm>node console.js (node:23304) UnhandledPromiseRejectionWarning：未处理的承诺拒绝 (rejection id: 1): 发生错误。 （节点：23304）[DEP0018] DeprecationWarning：不推荐使用未处理的承诺拒绝。在 未来，未处理的承诺拒绝将终止 具有非零退出代码的 Node.js 进程。执行（默认）：SELECT 1+1 AS 结果 连接建立成功。

更新： 如果我像下面建议的那样在调用者周围放置一个 try/catch，我会得到更好的结果，但不确定 error message 在 connection message 之前是如何发生的？

C:\code\eca-contracts>node console.js
error has occurred.
Executing (default): SELECT 1+1 AS result
Connection has been established successfully.

Answer 1

您应该处理在Promise 中被拒绝的错误。调用 Promise 方法时使用trycatch。

(async () => {
    try {
        var results2 = await contracts.update(contractToUpdate);
        console.log(results2);
    } catch (error) {
        console.log(error);
    }
})();