NestJS 3 分钟搭好 MySQL + MongoDB，CRUD 复制粘贴直接运行

基于上一篇内容《为什么现代 Node 后端都选 NestJS + TypeScript？这组合真香了》，这篇文章继续写数据库的连接。

所以今天把MySQL、MongoDB全接上，做个小实例。朋友们项目里用什么数据库可以视情况而定。
这里的功能分别为：

MySQL：存用户
MongoDB：存日志

代码短、跟着敲就行。

1. 生成对应架构

执行以下命令生成相关模块代码（Module/Service/Controller）

nest g res user
nest g res log

2. 装包

pnpm i @nestjs/typeorm typeorm mysql2
pnpm i @nestjs/mongoose mongoose

3. 连库

在app.module.ts 一次配好

import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';
import { MongooseModule } from '@nestjs/mongoose';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { TodoModule } from './todo/todo.module';
import { UserModule } from './user/user.module';
import { LogModule } from './log/log.module';@Module({imports: [// MySQLTypeOrmModule.forRoot({type: 'mysql',host: 'localhost',port: 3306,username: 'root',password: 'SV^u8@rB8',database: 'demo',autoLoadEntities: true,synchronize: true, // 仅本地用，生产关掉}),// MongoDBMongooseModule.forRoot('mongodb://localhost:27017/test'),// 业务模块TodoModule,UserModule,LogModule,],controllers: [AppController],providers: [AppService],
})
export class AppModule {}

代码生成了，接下来我们来处理数据库和增删改查的代码。

Mysql

1. 实体和数据表

数据库表

CREATE TABLE `user` (`id` bigint NOT NULL AUTO_INCREMENT COMMENT '主键',`name` varchar(255) COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '用户名',`age` int DEFAULT NULL COMMENT '年龄',PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci COMMENT='用户表';

MySQL 实体

// user.entity.ts
import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';@Entity()
export class User {@PrimaryGeneratedColumn() id: number;@Column() name: string;@Column() age: number;
}

Dto

// create-user.dto.ts
export class CreateUserDto {name: string;age: number;
}

这里容易出现一个Eslint问题的爆红，如下图：

出现这种情况执行以下命令：

npx eslint "src/**/*.{ts,js}" --fix --ext .ts,.js

如果还是不行，再执行下这个

npx prettier --write "src/**/*.{ts,js,json}"

2. 业务代码(cv即可)

user.controller.ts

import { Controller, Get, Post, Body, Patch, Param, Delete,} from '@nestjs/common';
import { UserService } from './user.service';
import { CreateUserDto } from './dto/create-user.dto';
import { UpdateUserDto } from './dto/update-user.dto';@Controller('user')
export class UserController {constructor(private readonly userService: UserService) {}@Post()create(@Body() createUserDto: CreateUserDto) {return this.userService.create(createUserDto);}@Get()findAll() {return this.userService.findAll();}@Get(':id')findOne(@Param('id') id: string) {return this.userService.findOne(+id);}@Patch(':id')update(@Param('id') id: string, @Body() updateUserDto: UpdateUserDto) {return this.userService.update(+id, updateUserDto);}@Delete(':id')remove(@Param('id') id: string) {return this.userService.remove(+id);}
}

user.module.ts

这里稍微的修改了一下，引入了TypeOrmModule

import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';
import { UserService } from './user.service';
import { UserController } from './user.controller';
import { User } from './entities/user.entity';@Module({imports: [TypeOrmModule.forFeature([User])],controllers: [UserController],providers: [UserService],
})
export class UserModule {}

user.service.ts

完成了增删改查的业务代码

import { Injectable } from '@nestjs/common';
import { CreateUserDto } from './dto/create-user.dto';
import { UpdateUserDto } from './dto/update-user.dto';
import { User } from './entities/user.entity';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';@Injectable()
export class UserService {constructor(@InjectRepository(User)private readonly repo: Repository<User>,) {}async create(createUserDto: CreateUserDto): Promise<User> {return await this.repo.save(createUserDto);}async findAll(): Promise<User[]> {return await this.repo.find();}async findOne(id: number): Promise<User> {const user = await this.repo.findOne({ where: { id } });if (!user) {throw new Error(`User with ID ${id} not found`);}return user;}async update(id: number, updateUserDto: UpdateUserDto): Promise<User> {const user = await this.findOne(id);Object.assign(user, updateUserDto);return await this.repo.save(user);}async remove(id: number): Promise<void> {const user = await this.findOne(id);await this.repo.remove(user);}
}

3. 跑起来，测试下接口

npm run start

新增

POST http://localhost:3000/user

{ "name": "张三", "age": 30 }

修改

POST http://localhost:3000/user

{ "id": 1, "name": "张三", "age": 31 }

删除

DELETE http://localhost:3000/user/1

查询

GET http://localhost:3000/user/1

这里实现mysql的增删改查就完成了

MongoDB

大致流程和mysql是一样的，写法稍微有些差别

1. 实体和集合

创建一个集合

db.createCollection("logs");

集合实体

// log.entity.ts
import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
import { Document, Types } from 'mongoose';export type LogDocument = Log & Document;@Schema()
export class Log {_id?: Types.ObjectId;@Prop({ required: true })message: string;@Prop({ default: Date.now })timestamp: Date;
}export const LogSchema = SchemaFactory.createForClass(Log);

Dto

// create-log.dto.ts
export class CreateLogDto {message: string;timestamp?: Date;
}

2. 业务代码(cv即可)

log.controller.ts

import {Controller, Get, Post, Body, Patch, Param, Delete} from '@nestjs/common';
import { LogService } from './log.service';
import { CreateLogDto } from './dto/create-log.dto';
import { UpdateLogDto } from './dto/update-log.dto';@Controller('log')
export class LogController {constructor(private readonly logService: LogService) {}@Post()create(@Body() createLogDto: CreateLogDto) {return this.logService.create(createLogDto);}@Get()findAll() {return this.logService.findAll();}@Get(':id')findOne(@Param('id') id: string) {return this.logService.findOne(id);}@Patch(':id')update(@Param('id') id: string, @Body() updateLogDto: UpdateLogDto) {return this.logService.update(id, updateLogDto);}@Delete(':id')remove(@Param('id') id: string) {return this.logService.remove(id);}
}

log.module.ts

引入了MongooseModule

import { Module } from '@nestjs/common';
import { MongooseModule } from '@nestjs/mongoose';
import { LogService } from './log.service';
import { LogController } from './log.controller';
import { Log, LogSchema } from './entities/log.entity';@Module({imports: [MongooseModule.forFeature([{ name: Log.name, schema: LogSchema }])],controllers: [LogController],providers: [LogService],
})
export class LogModule {}

user.service.ts

增删改查的业务代码

import { Injectable } from '@nestjs/common';
import { InjectModel } from '@nestjs/mongoose';
import { Model } from 'mongoose';
import { CreateLogDto } from './dto/create-log.dto';
import { UpdateLogDto } from './dto/update-log.dto';
import { Log, LogDocument } from './entities/log.entity';@Injectable()
export class LogService {constructor(@InjectModel(Log.name) private logModel: Model<LogDocument>) {}async create(createLogDto: CreateLogDto): Promise<Log> {const createdLog = new this.logModel(createLogDto);return createdLog.save();}async findAll(): Promise<Log[]> {return this.logModel.find().exec();}async findOne(id: string): Promise<Log> {const log = await this.logModel.findById(id).exec();if (!log) {throw new Error(`Log with ID ${id} not found`);}return log;}async update(id: string, updateLogDto: UpdateLogDto): Promise<Log> {const updatedLog = await this.logModel.findByIdAndUpdate(id, updateLogDto, { new: true }).exec();if (!updatedLog) {throw new Error(`Log with ID ${id} not found`);}return updatedLog;}async remove(id: string): Promise<void> {const result = await this.logModel.findByIdAndDelete(id).exec();if (!result) {throw new Error(`Log with ID ${id} not found`);}}
}

3. 启动，测试接口

npm run start

新增

POST http://localhost:3000/log

{ "message": "张三的消息" }

修改

POST http://localhost:3000/log

{ "id": 1, "message": "李四的消息"}

删除

DELETE http://localhost:3000/log/1

查询

GET http://localhost:3000/log/1

MongoDB的增删改查完成

小结

MySQL：使用TypeORM实体一把梭
MongoDB：使用Schema装饰器直接上

NestJS真的是结构清晰，开发很快，再也不用从头造轮子了。

我是大华，专注分享前后端开发的实战笔记。关注我，少走弯路，一起进步！

📌往期精彩

《Elasticsearch 太重？来看看这个轻量级的替代品 Manticore Search》

《别再if套if了！Java中return的9种优雅写法》

《别学23种了！Java项目中最常用的6个设计模式，附案例》

《写给小公司前端的 UI 规范：别让页面丑得自己都看不下去》

《Vue3+TS设计模式：5个真实场景让你代码更优雅》