11

我在 Node.JS 中使用 TypeORM，并希望使用实体继承来实现 BaseRecord：

export abstract class BaseRecord {
  @CreateDateColumn({type: 'timestamp'})
  public created_at: Date;

  @UpdateDateColumn({type: 'timestamp'})
  public updated_at: Date;

  @ManyToOne(type => User, user => user.records_created)
  public created_by: User

  @ManyToOne(type => User, user => user.records_updated)
  public updated_by: User
}

我想通过它来扩展其他实体。这在删除 @ManyToOne 关系时按预期工作：

@Entity()
export class Address extends BaseRecord {
  @PrimaryGeneratedColumn()
  public id: number;

  @Column({ nullable: true, type: "text" })
  public alias: string;

  @Column({ type: "text" })
  public street_1: string;

  @Column({ nullable: true, type: "text" })
  public street_2: string;

  @Column({ type: "text" })
  public city: string;

  @Column({ type: "text" })
  public state: string;

  @Column({ type: "text" })
  public zip_code: string;

  @Column(type => GeoLocation)
  public geo_location: GeoLocation
}

有没有人遇到过这个或继承实体并具有多对一关系的方法？

4

1 回答 1

4

我建议在嵌入实体中使用组合而不是继承

嵌入列是接受具有自己的列的类并将这些列合并到当前实体的数据库表中的列。

您可以根据需要在嵌入式类中使用尽可能多的列（或关系）。您甚至可以在嵌入式类中嵌套嵌入式列。

import {Column} from "typeorm";

export class Assigned {
    @ManyToOne(type => User, user => user.records_created)
    public created_by: User

    @ManyToOne(type => User, user => user.records_updated)
    public updated_by: User
}

export class Dated {
    @CreateDateColumn({type: 'timestamp'})
    public created_at: Date;

    @UpdateDateColumn({type: 'timestamp'})
    public updated_at: Date;
}

然后使用它

import {Entity, PrimaryGeneratedColumn, Column} from "typeorm";
import {Assigned} from "./Assigned";
import {Dated} from "./Dated";

@Entity()
export class Address extends BaseRecord {
  // ...Other columns

  @Column(type => Assigned)
  assigned: Assigned;

  @Column(type => Dated)
  dated: Dated;
}

您可以根据需要在嵌入式类中使用尽可能多的列（或关系）。您甚至可以在嵌入式类中嵌套嵌入式列。

于 2019-11-29T02:42:40.583 回答