Sequelize简单使用

• 安装
  npm install --save sequelize
• 安装驱动

One of the following:

npm install --save mysql2 //这个比较多
npm install --save sqlite3
$ npm install --save tedious # Microsoft SQL Server

• 链接数据库
  const sequelize = new Sequelize('库名', 'root', '123456', {
  host: 'localhost',
  dialect: 'mysql',
  });
  中文文档：https://www.sequelize.com.cn/core-concepts/model-querying-basics
• 链接测试
  sequelize
  .authenticate()
  .then(() => {
  console.log('Connection has been established successfully.');
  })
  .catch(err => {
  console.error('Unable to connect to the database:', err);
  });
• 建立模型 //就是查找的格式

const Article = sequelize.define('article', {
     title: {
        type: Sequelize.STRING
    }
}, {
    freezeTableName: true,
    timestamps: false,
});

• 查询

router.get('/Article', async ctx => {
    ctx.body = await Article.findAll()
})

• 插入数据

  第一种方法 // const jane = Article.build({ title: "C程9" });
    // await jane.save();
  
  第二种方法（常用）  const jane = await Article.create({ title: "Jane" });
router.post('/issue', async ctx => {
    console.log("ctx.request.body", ctx.request.body)   
    console.log("ctx.request.files", ctx.request.files)     //文件
    console.log("ctx.request.fields", ctx.request.fields) //表单
    let { title, catalogs, tags, contents } = ctx.request.fields
    console.log(title, catalogs, tags, contents)
    Article.create({ title: title, catalogs: catalogs, tags: tags, content: contents })
})

• 删除数据

router.post('/problem/catalog/delete/id', async ctx => {
    let { id } = ctx.request.fields
    Catalog.destroy({ where: { ID: id } })
    ctx.response = 'success'
})

• 更新数据

const jane = await User.create({ name: "Jane" });
console.log(jane.name); // "Jane"
jane.name = "Ada";
// 数据库中的名称仍然是 "Jane"
await jane.save();
// 现在该名称已在数据库中更新为 "Ada"！

-删除

const jane = await Article.create({ name: "Jane" });
console.log(jane.name); // "Jane"
await jane.destroy();
// 现在该条目已从数据库中删除

• 重载

const jane = await Article.create({ name: "Jane" });
console.log(jane.name); // "Jane"
jane.name = "Ada";// 数据库中的名称依然是 "Jane"await jane.reload();console.log(jane.name); // "Jane"

reload 调用生成一个 SELECT 查询,以从数据库中获取最新数据.