全栈项目|小书架|服务器开发-NodeJS 中使用 Sequelize 操作 MySQL数据库

小咪咪 2023-06-13 04:44 28阅读 0赞

## 安装 ##

> 官网：https://sequelize.org/v5/manual/getting-started.html

安装`sequelize`及数据库连接驱动

npm install --save sequelize
    $ npm install --save mysql2

## 使用 ##

**创建连接：**

const Sequelize = require('sequelize');
    const sequelize = new Sequelize('database', 'username', 'password', {
      host: 'localhost',
      dialect: 'mysql'
    });

**创建Model表：**

const Model = Sequelize.Model;
    class User extends Model {}
    User.init({
      // attributes
      firstName: {
        type: Sequelize.STRING,
        allowNull: false
      },
      lastName: {
        type: Sequelize.STRING
        // allowNull defaults to true
      }
    }, {
      sequelize,
      modelName: 'user'
      // options
    });

**生产数据:**

// Note: using `force: true` will drop the table if it already exists
    User.sync({ force: true }).then(() => {
      // Now the `users` table in the database corresponds to the model definition
      return User.create({
        firstName: 'John',
        lastName: 'Hancock'
      });
    });

### 增加数据 ###

// Create a new user
    User.create({ firstName: "Jane", lastName: "Doe" }).then(jane => {
      console.log("Jane's auto-generated ID:", jane.id);
    });

### 删除数据 ###

// Delete everyone named "Jane"
    User.destroy({
      where: {
        firstName: "Jane"
      }
    }).then(() => {
      console.log("Done");
    });

### 改变数据 ###

// Change everyone without a last name to "Doe"
    User.update({ lastName: "Doe" }, {
      where: {
        lastName: null
      }
    }).then(() => {
      console.log("Done");
    });

### 查询数据 ###

// Find all users
    User.findAll().then(users => {
      console.log("All users:", JSON.stringify(users, null, 4));
    });

### 数据类型 ###

> https://sequelize.org/v5/manual/data-types.html

### Model 使用 ###

> https://sequelize.org/v5/manual/models-usage.html

### Model 查询 ###

> https://sequelize.org/v5/manual/querying.html

### 数据迁移 ###

> https://sequelize.org/v5/manual/migrations.html

对于数据迁移这块，笔者目前实际使用还是不熟练，比如 `model`添加了新的字段如何处理、开发环境和生产环境新添加字段或者删除字段怎么处理 ，希望有熟悉的朋友能够指导一二，不胜感激。

[参考1：Sequelize 和 MySQL 对照][1_Sequelize _ MySQL]  
[参考2：Getting started-Sequelize][2_Getting started-Sequelize]

--------------------

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[1_Sequelize _ MySQL]: https://segmentfault.com/a/1190000003987871#articleHeader0
[2_Getting started-Sequelize]: https://sequelize.org/v5/manual/getting-started.html
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