nestjs（2）连接数据库

安装typeorm与mysql

npm i --save @nestjs/typeorm typeorm mysql

新建User实体类

在src目录下新建entities目录，用于存放实体类。
在entities目录下新建User实体类，该实体类有id、name、age三个字段

src
|--entities
|--|--User.entity.ts

User.entity.ts:

import { Entity, Column, PrimaryGeneratedColumn } from 'typeorm'

@Entity()
export class User {
    @PrimaryGeneratedColumn() // 自动生成id
    id: number

    @Column()
    name: string

    @Column()
    age: number
}

新建userController、userService、userModule

nest g co /user
nest g s /user
nest g mo /user

src
|--entities
|--user
|--|--user.controller.ts
|--|--user.module.ts
|--|--user.service.ts

user.controller.ts:
编写了三个路由，通过监听GET请求，分别调用root、save、get、remove这四个方法

import { Controller, Get, Query } from '@nestjs/common'
import { UserService } from './user.service'
import { User } from '../entities/user.entity'

@Controller('user')
export class UserController {
    constructor(private readonly userSrvice: UserService) {}

    @Get()
    root(): string{
        return this.userSrvice.root()
    }

    @Get('save')
    save(@Query() query): any{

        console.log(query)
        let user = new User()
        user.name = query.name
        user.age = Number(query.age)
        if(query.id){
            user.id = Number(query.id)
        }

        return this.userSrvice.save(user)
    }

    @Get('get')
    get(@Query() query): any{

        if(query.id){
            query.id = Number(query.id)
        }
        if(query.age){
            query.age = Number(query.age)
        }
        return this.userSrvice.get(query)
    }
    
    @Get('remove')
    remove(@Query() query): any{

        if(query.id){
            query.id = Number(query.id)
        }
        if(query.age){
            query.age = Number(query.age)
        }
        return this.userSrvice.remove(query)
    }
}

user.service.ts:
实现了对user表的增删查改操作

import { Injectable } from '@nestjs/common'
import { User } from '../entities/user.entity'
import { InjectRepository } from '@nestjs/typeorm'
import { Repository } from 'typeorm'

@Injectable()
export class UserService {

    constructor(@InjectRepository(User) 
                private readonly userRepository: Repository) { }
    
    root(): string {
        return 'userService'
    }

    // 当user带有id时，save = update；当user没有id时，save = add
    async save(user: User): Promise {
        let res = await this.userRepository.save(user)
        console.log("save: ", res)

        return res
    }

    async getAll(): Promise {
        let res = await this.userRepository.find()
        console.log("all user: ", res)

        return res
    }

    async get(option: object): Promise {
        let res = await this.userRepository.find(option)
        // let res = await this.userRepository.find({name: 'longmao'})
        console.log("option user: ", res)

        return res
    }

    async remove(option: object): Promise {
        let user = await this.userRepository.find(option)

        let res = await this.userRepository.remove(user)

        console.log("remove: ", res)

        return res
    }
}

user.module.ts:
通过TypeOrmModule.forFeature([User])获取数据库的user表实例

import { Module } from '@nestjs/common'
import { TypeOrmModule } from '@nestjs/typeorm'
import { UserController } from './user.controller'
import { UserService } from './user.service'
import { User } from '../entities/user.entity'

@Module({
  imports: [TypeOrmModule.forFeature([User])],
  controllers: [UserController],
  providers: [UserService]
})
export class UserModule {}

连接数据库

新建一个database和mysql用户供当前项目使用

mysql -u root -p
mysql> create database your_database character set utf8;
mysql> create user 'your_name'@'%' identified by 'your_password';
mysql> grant all privileges on your_database.* to 'your_name'@'%';
mysql> flush privileges;
mysql> exit;

app.module.ts:
修改app.module.ts中的imports字段，让nest连接上数据库

import { Module } from '@nestjs/common'
import { AppController } from './app.controller'
import { AppService } from './app.service'
import { UserModule } from './user/user.module'
import { TypeOrmModule } from '@nestjs/typeorm'
import { User } from './entities/user.entity'

@Module({
  imports: [TypeOrmModule.forRoot({
    "type": "mysql",
    "host": "localhost",
    "port": 3306,
    "username": "fund_game",
    "password": "fund_game",
    "database": "fund_game",
    "synchronize": true,
    "entities": [User],
  }), UserModule],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}

测试运行效果

npm run start

第一次运行时会自动创建User表

向User表添加数据：浏览器访问localhost:3000/user/save?name=xxx&age=18

更新User表的数据：浏览器访问localhost:3000/user/get?name=xxx&age=18&id=1

查询User表的数据：浏览器访问localhost:3000/user/get?name=xxx&age=18

删除User表的数据：浏览器访问localhost:3000/user/remove?name=xxx&age=18