如何解决试图持久化未发现的对象类型实体
问题
我是 nest.js
和 Mikro-ORM
的新手,我必须根据工作要求学习它们。
这个栈需要TypeScript
,我打从心底鄙视它,但它必须完成。
我已经设置了我的应用程序,当我执行 npm run start:dev
时,它可以正常启动。
但是,当我尝试向数据库添加内容时,它突然消失并给出以下错误块:
[nest] 5368 - 07/03/2021,11:52:15 PM [ExceptionsHandler] Trying to persist not discovered entity of type object. +183188ms
ValidationError: Trying to persist not discovered entity of type object.
at Function.notdiscoveredEntity (/home/lazar/tuts/backend/node_modules/@mikro-orm/core/errors.js:51:16)
at sqlEntityManager.persist (/home/lazar/tuts/backend/node_modules/@mikro-orm/core/EntityManager.js:438:48)
at sqlEntityManager.persistAndFlush (/home/lazar/tuts/backend/node_modules/@mikro-orm/core/EntityManager.js:449:20)
at sqlEntityRepository.persistAndFlush (/home/lazar/tuts/backend/node_modules/@mikro-orm/core/entity/EntityRepository.js:21:23)
at UseRSService.create (/home/lazar/tuts/backend/dist/users/users.service.js:47:35)
at UsersController.create (/home/lazar/tuts/backend/dist/users/users.controller.js:25:40)
at /home/lazar/tuts/backend/node_modules/@nestjs/core/router/router-execution-context.js:38:29
at processticksAndRejections (internal/process/task_queues.js:97:5)
at async /home/lazar/tuts/backend/node_modules/@nestjs/core/router/router-execution-context.js:46:28
at async /home/lazar/tuts/backend/node_modules/@nestjs/core/router/router-proxy.js:9:17
这是我第一次走进这个堆栈,我不知道错误意味着什么。当我谷歌这个错误时,我没有得到任何有用的信息。我该怎么做才能让它消失?
相关代码
- 实体 (
User.ts
)
import { Entity,PrimaryKey,Property } from "@mikro-orm/core";
@Entity()
export class User {
@PrimaryKey()
id!: string;
@property()
email!: string;
@property()
name!: string;
@property()
password!: string;
@Property({ type: 'date' })
createdAt = new Date()
@Property({ type: 'date',onUpdate: () => new Date() })
updatedAt = new Date()
};
- 控制器 (
users.controller.ts
)
import { Body,Controller,Delete,Get,Param,Post,Put } from '@nestjs/common';
import { createuserDTO } from './dto/create-user.dto';
import { User } from './interfaces/user.interface';
import { UseRSService } from './users.service';
import { User as UserEntity } from "../entities/User"
@Controller('users')
export class UsersController {
constructor(private useRSService: UseRSService) {}
@Post()
async create(@Body() createuserDto: createuserDTO): Promise<User> {
console.log("createuserDTO",createuserDto);
return await this.useRSService.create(createuserDto)
}
}
- 服务 (
users.service.ts
)
import { EntityRepository } from '@mikro-orm/core';
import { Injectable } from '@nestjs/common';
import { User } from './interfaces/user.interface';
import { User as UserEntity } from "../entities/User"
import { InjectRepository } from '@mikro-orm/nestjs';
@Injectable()
export class UseRSService {
constructor(
@InjectRepository(UserEntity)
private readonly userRepository: EntityRepository<UserEntity>
) {}
async create(user: User): Promise<UserEntity> {
console.log("ALL GOOD");
const newUser = this.userRepository.create(user)
console.log("ALL GOOD");
console.log("NEW USER",newUser);
await this.userRepository.persistAndFlush(user)
console.log("ALL GOOD");
return newUser
}
}
- 模块 (
users.module.ts
)
import { MikroOrmModule } from '@mikro-orm/nestjs';
import { Module } from '@nestjs/common';
import { User } from 'src/entities/User';
import { UsersController } from './users.controller';
import { UseRSService } from './users.service';
@Module({
imports: [MikroOrmModule.forFeature([User])],controllers: [UsersController],providers: [UseRSService],exports: [UseRSService]
})
export class UsersModule {}
- DTO
export class createuserDTO {
readonly name: string;
readonly email: string;
readonly password: string;
readonly createdAt: Date;
readonly updatedAt: Date;
}
- 界面
export interface User {
id?: string;
name: string;
email: string;
password: string;
createdAt: Date;
updatedAt: Date;
}
解决方法
正如 Micael Levi 已经在评论中指出的那样,这是由于您试图持久化 POJO/DTO 而不是实体实例造成的。
const dto = { name: '...',email: '...' };
const user = em.create(User,dto);
// this is basically what you are doing and will fail as the prototype
// is just `Object` - which is what you see in the error
em.persist(dto);
// and this is what you need to do instead
em.persist(user);
您始终需要使用实体实例,以便 ORM 知道要使用哪些元数据。如果您只有 Object
,则无法将对象与正确的数据库表相关联。
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