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What seems to us as bitter trials are often blessings in disguise.
看起来对我们痛苦的试炼，常常是伪装起来的好运。

使用ORM框架sequelize完成Mysql数据库操作

使用ts实现mysql配置/泛型+重载

配置接口实现

创建src/config/DbConfig.ts文件

interface DbConfig{
    host: string, // 可选
    user: string,
    password: string,
    port: number,
    database: string
}
// 环境接口
interface EnvConf{
    dev:DbConfig,
    prod:DbConfig
}

实现环境配置类

• package.json设置环境变量

dev: set NODE_ENV=dev && nodemon --watch src/ -e ts --exec ts-node ./src/app.ts
prod: set NODE_ENV=prod && nodemon --watch src/ -e ts --exec ts-node ./src/app.ts

完善DbConfig.ts文件

function isString(data: any): data is string {
    return typeof data === 'string'
}
interface DbConfig {
    host: string, // 可选
    user: string,
    password: string,
    port: number,
    database: string
}
// 环境接口
interface EnvConf {
    dev: DbConfig,
    prod: DbConfig
}
class Conf {
    static conf: Conf = new Conf()
    env!: keyof EnvConf
    envConf!: EnvConf
    constructor() {
        console.log(process.env.NODE_ENV)
        this.env = process.env.NODE_ENV === "dev"?"dev":"prod"
        console.log(this.env)
        this.initConf()
    }
    initConf() {
        this.envConf = {
            dev: {
                host: "192.168.136.129", 
                user: "admin",
                password: "root",
                port: 3306,
                database: "test"
            },
            prod: {
                host: "www.test.com", 
                user: "admin",
                password: "root",
                port: 3306,
                database: "test"
            }
        }
    }
    getConf():DbConfig
    getConf(key:string):string
    getConf(key:any=''):any{
        if(this.isDbConConfKeys(key)&&key.length>0){
            return this.envConf[this.env][key]
        }else{
            return this.envConf[this.env]
        }
    }
    isDbConConfKeys(key:any):key is keyof DbConfig{
        return key === 'host' || key === 'user' || key === 'password' || key === 'database'
    }
}
export default Conf.conf

app.ts引入测试

import dbconfig from './conf/DbConfig'
console.log(dbconfig.getConf())

ORM sequelize框架

ORM

ORM避免直接编写sql语句带来的繁琐，把关系型数据表直接映射为js对象查询，同时也将js对象转换为关系型数据表进行增删改

sequelize

基于promise的node.js ORM，支持postgres，mysql，mariadb，sqlite，mssql

• 支持事务
• 支持一对一，一对多，多对一，多对多 关联表映射

使用sequelize实现crud

sequelize连接mysql

创建src/dao/BaseDaoDefine.ts文件

import dbConfig from "@/conf/DbConfig";
import { Dialect } from "sequelize";
import { Sequelize } from "sequelize-typescript";
class BaseDaoDefine{
    static baseDaoOrm:BaseDaoDefine = new BaseDaoDefine()
    sequelize!:Sequelize
    constructor(){
        this.initSeqConf('mysql')
    }
    initSeqConf(dialect:Dialect){
        let {host,user,password,database,port} = dbConfig.getConf()
        this.sequelize = new Sequelize(database,user,password,{
            host,
            port,
            dialect, // 方言 数据库类型
            define:{timestamps:false,freezeTableName:true}
        })
    }
}
export const {sequelize} = BaseDaoDefine.baseDaoOrm

执行3种查询

使用sequelize define方法定义一个模型实现

• 适合对单表进行各种查询
• 适合单表添加，更新
• 适合多表级联添加，更新
• 不适合多表级联查询，有差异

使用sequelize原生操作

• 适合所有场景

使用模型类来实现

• 最适合对单表进行各种查询