建立连接

const Sequelize = require('sequelize');
const sequelize = new Sequelize('database', 'username', 'password', {
    host: 'host',
    port: 'port',
    pool: {
        max: 50,
        min: 0,
        //建立连接最长时间
        acquire: 30000,
        //空闲最长连接时间
        idle: 10000
    },
    //默认输出执行sql语句
    logging: console.log,
    define: {
        //默认创建表有 createAt, updateAt
        timestamps: false,
        //可以给表设置别名
        freezeTableName: true,
        // 字段以下划线（_）来分割（默认是驼峰命名风格）
        underscored: false
    },
    //sequelize v4 必须设置方言
    dialect: 'mysql',
    //默认DECIMAL and NEWDECIMAL 返回 String
    dialectOptions: {
        decimalNumbers: true
    },
    //设置别名，否则不识别$like等关键词($like: Op.like对应关系)
    operatorsAliases: 'object',
    //时间上的统一
    timezone: "+08:00",
})

模型定义

const DataTypes = Sequelize.DataTypes;
const user = sequelize.define('u', {
    userId: {
        type: DataTypes.INTEGER,
        primaryKey: true,
        autoIncrement: true
    },
    userName: {
        type: DataTypes.STRING,
        allowNull: true
    },
    birthDay: {
        type: 'TIMESTAMP',
        allowNull: false
    },
    gender: {
        type: DataTypes.INTEGER,
        allowNull: true,
        defaultValue: 0
    },
    ctime: {
        type: 'TIMESTAMP',
        allowNull: false,
        defaultValue: Sequelize.literal('CURRENT_TIMESTAMP')
    },
    updatedAt: {
        type: 'TIMESTAMP',
        defaultValue: Sequelize.literal('CURRENT_TIMESTAMP'),
        field: 'ctime'
    }
}, {
        tableName: 'user'
    })

const products = sequelize.define('p', {
    prdId: {
        type: DataTypes.INTEGER,
        primaryKey: true,
        autoIncrement: true
    },
    prdName: {
        type: DataTypes.STRING,
        allowNull: false
    },
    userId: {
        type: DataTypes.INTEGER,
        allowNull: false
    },
    price: {
        type: DataTypes.DECIMAL(5, 4),
        allowNull: false
    }
})
products.belongsTo(user, { foreignKey: 'userId', targetKey: 'userId', as: 'u' });

注意点：
1. type 如果不存在则直接用字符串表示 如：’TIMESTAMP’;
2. 如果需要在更新表字段时记录更新时间，可应使用 updateAt，并设置默认值和对应的字段名。
3. 如果默认值不是具体的数值，可以用 literal 函数去表示。
4. tableName 表名，u 为别名。
5. 建立关联关系时，如果外键关联的是主键则不用写 targetKey，否则需要。

查询

方式一

products.findAll({
    attributes: ['prdName', 'price'],
    include: [{
        model: user,
        as: 'u',
        attributes: ['userName']
    }],
    //raw:true
}).then(result => {
    console.log(JSON.stringify(result))
}).catch(err => {
    console.log(err)
});

结果：

[
    {
        "prdName": "ipad",
        "price": 4.99,
        "u": { "userName": "张三" }
    },
    {
        "prdName": "iphone",
        "price": 3.658,
        "u": { "userName": "张三" }
    },
    {
        "prdName": "联想笔记本",
        "price": 9.32,
        "u": { "userName": "李四" }
    }
]

方式二

products.findAll({
    attributes: ['prdName', 'price'],
    include: [{
        model: user,
        as: 'u',
        attributes: ['userName']
    }],
    raw:true
}).then(result => {
    console.log(JSON.stringify(result))
}).catch(err => {
    console.log(err)
});

结果：

[
    {
        "prdName":"ipad",
        "price":4.99,
        "u.userName":"张三"
    },
    {
        "prdName":"iphone",
        "price":3.658,
        "u.userName":"张三"
    },
    {
        "prdName":"联想笔记本",
        "price":9.32,
        "u.userName":"李四"
    }
]

方式三

products.findAll({
    attributes: [Sequelize.col('u.userName'),'prdName', 'price'],
    include: [{
        model: user,
        as: 'u',
        attributes: []
    }],
    raw:true
}).then(result => {
    console.log(JSON.stringify(result))
}).catch(err => {
    console.log(err)
});

结果：

[
    {
        "userName":"张三",
        "prdName":"ipad",
        "price":4.99
    },
    {
        "userName":"张三",
        "prdName":"iphone",
        "price":3.658
    },
    {
        "userName":"李四",
        "prdName":"联想笔记本",
        "price":9.32
    }
]

 加条件的写法：

products.findAll({
    attributes: [Sequelize.col('u.userName'), 'prdName', 'price'],
    include: [{
        model: user,
        as: 'u',
        attributes: []
    }],
    where: {
        prdName: 'ipad',
        '$u.userId$': 1
    },
    raw: true
}).then(result => {
    console.log(JSON.stringify(result))
}).catch(err => {
    console.log(err)
})

对应sql:
SELECT u.userName, p.prdName, p.price FROM products AS p LEFT OUTER JOIN user AS u ON p.userId = u.userId WHERE p.prdName = ‘ipad’ AND u.userId = 1;
注：如果给include 表加where条件 须使用'$u.userId$'这种写法;也可在include加where条件

事务

function doit() {
    //启用事务(自动提交)
    return sequelize.transaction(function (t) {
        return user.create({
            userName: '黄晓明',
            birthDay: '1991-06-23',
            gender: 0
        }, {
                transaction: t
            }).then(result => {
                return user.update({
                    userName: '李四',
                }, {
                        where: { userId: result.userId },
                        transaction: t  //注意（事务transaction 须和where同级）second parameter is "options", so transaction must be in it
                    })
            })
    }).then(result => {
        // Transaction 会自动提交
        // result 是事务回调中使用promise链中执行结果
        // console.log(result.length)
        console.log("ok")
    }).catch(err => {
        // Transaction 会自动回滚
        // err 是事务回调中使用promise链中的异常结果
        console.log(err)
    })
}

 循环：

const Op = Sequelize.Op;
const Promise = require('bluebird');
function recycle() {
    let tranArray = [];
    products.findAll({
        attributes: ['prdId', 'prdName', 'userId', 'price'],
        raw: true
    }).then(result => {
        result.forEach(rec => {
            tranArray.push(products.create({
                prdName: rec.prdName,
                userId: rec.userId,
                price: rec.price
            }))
        })
        return Promise.all(tranArray)
    }).then(result => {
        console.log('result' + result)
    }).catch(err => {
        console.log('err' + err)
    })
}