sequelize.js

(async () => {
    const Sequelize = require("sequelize");

    // 建立连接
    const sequelize = new Sequelize("kaikeba", "root", "example", {
        host: "localhost",
        dialect: "mysql",
        operatorsAliases: false
    });

    // 定义模型
    const Fruit = sequelize.define("Fruit", {
        name: {
            type: Sequelize.STRING(20),
            allowNull: false,
            // get() {
            //     const fname = this.getDataValue("name");
            //     const price = this.getDataValue("price");
            //     const stock = this.getDataValue("stock");
            //     return `${fname}(价格：￥${price} 库存：${stock}kg)`;
            // }
        },
        price: {
            type: Sequelize.FLOAT,
            allowNull: false,
            validate: {
                isFloat: { msg: "价格字段请输入数字" },
                min: { args: [0], msg: "价格字段必须大于0" }
            }
        },
        stock: { type: Sequelize.INTEGER, defaultValue: 0 },

    },
        {
            timestamps: false,
            getterMethods: {
                amount() {
                    return this.getDataValue("stock") + "kg";
                }
            },
            setterMethods: {
                amount(val) {
                    const idx = val.indexOf('kg');
                    const v = val.slice(0, idx);
                    this.setDataValue('stock', v);
                }
            }
        });

    Fruit.classify = function (name) {
        const tropicFruits = ['香蕉', '芒果', '椰子']; // 热带水果
        return tropicFruits.includes(name) ? '热带水果' : '其他水果';
    };
    Fruit.prototype.totalPrice = function (count) {
        return (this.price * count).toFixed(2);
    };

    ['香蕉', '草莓'].forEach(f => console.log(f + '是' + Fruit.classify(f)));

    // 同步数据库，force: true则会删除已存在表
    let ret = await Fruit.sync({ force: false })
    // console.log('sync', ret)
    ret = await Fruit.create({
        name: "香蕉",
        price: 3.5
    })
    // console.log('create', ret)
    // ret = await Fruit.findAll()

    // 使用实例方法
    // Fruit.findAll().then(fruits => {
    //     const [f1] = fruits;
    //     console.log(`买5kg${f1.name}需要￥${f1.totalPrice(5)}`);      
    // });

    // Fruit.findOne({ where: { name: "香蕉" } }).then(fruit => {
    //     // fruit是首个匹配项，若没有则为null
    //     console.log(fruit.get());
    // });

    // console.log('findAll', ret.amount, JSON.stringify(ret))

    // Fruit.findAll().then(fruits => {
    //     console.log(JSON.stringify(fruits));
    //     // 修改amount，触发setterMethods
    //     fruits[0].amount = '150kg';
    //     fruits[0].save();
    // });

    // Fruit.findOne({ attributes: ['name'] }).then(fruit => {
    //     // fruit是首个匹配项，若没有则为null
    //     console.log(fruit.get());
    // });

    // ret = await Fruit.findAll({
    //     offset: 3,
    //     limit: 3,
    // })
    // console.log('ret:', JSON.stringify(ret))

    const Op = Sequelize.Op;
    Fruit.findAll({
        // where: { price: { [Op.lt]:4 }, stock: { [Op.gte]: 100 } }
        where: { id: { [Op.lt]: 4, [Op.gt]: 2 } }
    }).then(fruits => {
        console.log(JSON.stringify(fruits))
        console.log(fruits.length);
    });

    // Fruit.destroy({ where: { id: 1 } }).then(r => console.log(r));
})()