（一）sequelize postgres连接

1. 安装相关模块
   • npm install sequelize
   • npm install pg
2. 创建连接

   // 引用sequelize
   const Sequelize = require('sequelize');
   
   // 连接数据库方式一
   const sequelize = new Sequelize('testDb', 'postgres', '1', {
       host: 'localhost',
       dialect: 'postgres',
       operatorsAliases: false,
   
       pool: {
           max: 5,
           min: 0,
           acquire: 30000,
           idle: 1000
       }
   });
   
   // 连接数据库方式二
   // const sequelize = new Sequelize('postgres://postgres:1@localhost:5432/testDb');
   
   // 验证是否连接成功
   sequelize
       .authenticate()
       .then(() => {
           console.log('Connection has been established successfully');
       })
       .catch(err => {
           console.log('Unable to connect to the database:', err);
       });

3. 创建模型

   const Account = sequelize.define('account', {
       id: {
           type: Sequelize.STRING(32),
           primaryKey: true
       },
       account: {
           type: Sequelize.STRING(20)
       },
       password: {
           type: Sequelize.STRING(20)
       }
   }, {
       timestamps: false,      // 默认创建createdAt和updatedAt字段,为false则不创建
       freezeTableName: true   // 默认创建表名为accounts,为true则为account
   });
4. 同步模型到数据库

   Account.sync({force: true}); // force: true 将会删除现有表,根据模型重新建表

5. 创建及查询

   Account.create({
       id: 'test',
       account: '4619',
       password: '4619'
   }).then(res => {
       // 返回创建对象的实例
   }, err => {
       console.log(err);
   });

   Account.findAll({
       raw: true
   }).then(rows => {
       // raw: true返回查询的表数据,默认为false返回查询实例
   }, err => {
       console.log(err);
   });

   sequelize文档 Getting started