(1) sequelize postgres connection

1. Install related modules
   • npm install sequelize
   • npm install pg
2. Create a connection

   // 引用sequelize
   const Sequelize = require('sequelize');
   
   // Connection to database mode one 
   const sequelize = new Sequelize('testDb', 'postgres', '1' , {
       host: 'localhost',
       dialect: 'postgres',
       operatorsAliases: false,
   
       pool: {
           max: 5,
           min: 0 ,
           acquire: 30000,
           idle: 1000
       }
   });
   
   // Connection to database method 2 
   // const sequelize = new Sequelize('postgres://postgres:1@localhost:5432/testDb');
   
   // Verify whether the connection is successful 
   sequelize
       .authenticate()
       .then(() => {
           console.log('Connection has been established successfully');
       })
       .catch(err => {
           console.log('Unable to connect to the database:', err);
       });

    

3. Create a model

   const Account = sequelize.define('account', {
       id: {
           type: Sequelize.STRING(32),
           primaryKey: true
       },
       account: {
           type: Sequelize.STRING(20)
       },
       password: {
           type: Sequelize.STRING(20)
       }
   }, {
       timestamps: false ,       // The createdAt and updatedAt fields are created by default, if false , 
       freezeTableName: true    // The name of the created table is accounts by default, and if it is true, it is account 
   });

    

4. Sync model to database

   Account.sync({force: true }); // force: true will delete the existing table and rebuild the table according to the model

    

5. Create and query

   Account.create({
       id: 'test',
       account: '4619',
       password: '4619' 
   }).then(res => {
        // return the instance of the created object 
   }, err => {
       console.log(err);
   });

   Account.findAll({
       raw: true 
   }).then(rows => {
        // raw: true returns the query table data, the default is false and returns the query instance 
   }, err => {
       console.log(err);
   });

   sequelize文档 Getting started