@芥末的糖 ---------- node连接数据库两种方式mysql和moogoDB

先做个总结：连接数据库是一个建库，建Schema的过程...之后就是利用实例化的对象进行数据库的操作...

1.moogoDB的连接

//database.js
var mongoose = require('mongoose')
mongoose.connect('mongodb://localhost:27017/lagou', {
  useNewUrlParser: true
})

var db = mongoose.connection
db.on('error', console.error.bind(console, 'connection error:'))
db.once('open', function () {
  // we're connected!
})

module.exports = mongoose

//某一个model的代码
const mongoose = require('../utils/database')

// 创建Schema，创建集合
const positionSchema = new mongoose.Schema({
  companyLogo: String,
  companyName: String,
  positionName: String,
  city: String,
  salary: String,
  createDate: String
})
const PositionModel = mongoose.model('positions', positionSchema)
//之后进行一些增删改查的操作

2.mysql的连接

//连接数据库
var mysql      = require('mysql');
var connection = mysql.createPool({
  connectionLimit : 10,
  host     : 'localhost',
  user     : 'root',
  password : '',
  database : 'gp7'
});
 //然后做增删改查的工作
//查
const _select = (sql) => {
  return new Promise((resolve, reject) => {
    connection.query('SELECT * FROM posts')//暂定查所有
      .on('error', (err) => {
        reject(err.message)
      })
      .on('result', (row) => {
        resolve(row)
      })
  })
}

详细的查询数据库的方法

moogoose

https://mongoosejs.com/docs/guide.html

mysql

https://www.npmjs.com/package/mysql