Nest 集成 Prisma

项目初始化及配置

创建 NestJS 项目

nest new nest-prisma-test -p npm
cd nest-prisma-test

安装 Prisma 并初始化

npm install prisma
npx prisma init

配置数据库连接

在生成的 .env 文件中设置数据库连接：

DATABASE_URL="mysql://root:自己的密码@localhost:3306/prisma_test"

修改生成的 schema.prisma 文件，配置数据源：

datasource db {
  provider = "mysql"
  url      = env("DATABASE_URL")
}

定义数据模型

在 schema.prisma 文件中定义数据模型：

model Department {
  id         Int        @id @default(autoincrement())
  name       String     @db.VarChar(20)
  createTime DateTime   @default(now())
  updateTime DateTime   @updatedAt
  employees  Employee[]
}

model Employee {
  id           Int        @id @default(autoincrement())
  name         String     @db.VarChar(20)
  phone        String     @db.VarChar(30)
  departmentId Int
  department   Department @relation(fields: [departmentId], references: [id])
}

数据库迁移与生成客户端代码

重置数据库

npx prisma migrate reset

创建并应用新的迁移

npx prisma migrate dev --name init

集成 Prisma 到 NestJS

创建 Prisma Service

nest g service prisma --flat --no-spec

在 PrismaService 类中，继承 PrismaClient 并初始化数据库连接：

import { Injectable, OnModuleInit } from '@nestjs/common';
import { PrismaClient } from '@prisma/client';

@Injectable()
export class PrismaService extends PrismaClient implements OnModuleInit {
  constructor() {
    super({
      log: [{ emit: 'stdout', level: 'query' }],
    });
  }

  async onModuleInit() {
    await this.$connect();
  }
}

创建业务逻辑服务

Department Service

nest g service department --flat --no-spec

实现部门创建功能：

import { Inject, Injectable } from '@nestjs/common';
import { PrismaService } from './prisma.service';
import { Prisma } from '@prisma/client';

@Injectable()
export class DepartmentService {
  @Inject(PrismaService)
  private prisma: PrismaService;

  async create(data: Prisma.DepartmentCreateInput) {
    return await this.prisma.department.create({
      data,
      select: { id: true },
    });
  }
}

Employee Service

nest g service employee --flat --no-spec

实现员工创建功能：

import { Inject, Injectable } from '@nestjs/common';
import { PrismaService } from './prisma.service';
import { Prisma } from '@prisma/client';

@Injectable()
export class EmployeeService {
  @Inject(PrismaService)
  private prisma: PrismaService;

  async create(data: Prisma.EmployeeCreateInput) {
    return await this.prisma.employee.create({
      data,
      select: { id: true },
    });
  }
}

实现 API 接口

在 AppController 中注入服务并创建接口：

import { Controller, Get, Inject } from '@nestjs/common';
import { DepartmentService } from './department.service';
import { EmployeeService } from './employee.service';

@Controller()
export class AppController {
  @Inject(DepartmentService) private departmentService: DepartmentService;
  @Inject(EmployeeService) private employeeService: EmployeeService;

  @Get('create')
  async create() {
    const department = await this.departmentService.create({ name: '技术部' });

    await this.employeeService.create({
      name: '云牧',
      phone: '123',
      department: { connect: { id: department.id } },
    });

    return 'done';
  }
}

启动项目

npm run start:dev

访问 http://localhost:3000/create 可以看到数据被插入数据库：