Sequelize 中未定义 findOne 属性答案

【问题标题】：findOne property not defined in SequelizeSequelize 中未定义 findOne 属性
【发布时间】：2019-03-06 03:13:12
【问题描述】：

我正在尝试使用 Sequelize 和 mysql db 创建一个模型。我正在尝试发布到“/students/register”，它一直给我一个错误，说 findOne 不是一个函数。我尝试要求我的 sql 但它不工作..我还尝试了一个不同的函数，如 findAll 并且仍然不工作。似乎是什么问题。谢谢

models/Students.js

const Sequelize = require('sequelize');
const sequelize = require('../database/db')

module.exports = (sequelize, Sequelize) => {
    const Student = sequelize.define(
        'student', {
            id: {
                type: Sequelize.INTEGER,
                primaryKey: true,
                autoIncrement: true
            },
            name: {
                type: Sequelize.STRING
            },
            email: {
                type: Sequelize.STRING
            },
            password: {
                type: Sequelize.STRING
            },
            created: {
                type: Sequelize.DATE,
                defaultValue: Sequelize.NOW
            }
        }, {
            timestamps: false
        });
    module.exports = Student;
};

数据库/db.js

   const Sequelize = require('sequelize')
const sequelize = new Sequelize('canavs', 'root', 'root', {
    host: 'localhost',
    port: 8889,
    dialect: 'mysql',
    operatorAliases: false,

    pool: {
        max: 5,
        min: 0,
        acquire: 3000,
        idle: 10000
    }
})
// sequelize.import('./models/Students')
module.exports = sequelize;

index.js

const Student_Info = require('./models/Students')
const db = require('./database/db')



// app.use('/students', Student)

app.get('/getName', (req, res) => {
    Student_Info.findOne({
            where: {
                id: 1
            }
        })
        .then((student) => {
            res.json(student.name);
        })
        .catch((err) => {
                res.send('error' + err)
            }

        )
})

【问题讨论】：

标签： mysql node.js express sequelize.js

【解决方案1】：

在student 模型定义中，您没有返回定义。

module.exports = (sequelize, Sequelize) => {
    const Student = sequelize.define(
        'student', {
            ...
        }, {
            timestamps: false
        });
    return Student; // You have to return the Student model in its definition
};

希望这会有所帮助...

【讨论】：

【解决方案2】：

让我们保持简单，只导出学生模型，无需导出 Sequelize/sequelize(db)，因为您可以要求它而不是导出要求它！

const Sequelize = require('sequelize');
const sequelize = require('../database/db');

const Student = connection.define('student', {

    name: Sequelize.STRING,
    email: {
        type: Sequelize.STRING,
        validate: {
            isEmail: true
        }
    },
    password: {
        type: Sequelize.STRING,
        validate: {
            isAlpha: true
        }
    }
});


module.exports = Student;

【讨论】：