复杂关系TypeORM / MySQL

Question

我在MySQL中使用TypeORM，我有两个实体，用户和项目：

@Entity()
class User {
    @PrimaryGeneratedColumn('uuid') 
    id: string;  

    @Column({})
    name: string;
}

@Entity()
class Project {
    @PrimaryGeneratedColumn('uuid') 
    id: string;  

    @Column({})
    name: string;
}

我想添加第三个实体，邀请。邀请由userId和作为关键字的projectId组成。一个用户可以被邀请到多个项目，但每个项目只能邀请一次。我还想存储发送邀请的用户。

@Entity()
class Invitation {
    @PrimaryGeneratedColumn('uuid') 
    id: string;  

    @Column({})
    userID: string;

    @Column({})
    invitedById: string;

    @Column({})
    projectID: string;

    @Column({})
    otherInformations: string;

}

如何使用TypeORM关系装饰器来实现这一点？

谢谢，感谢您的帮助，我对ORM世界还是很陌生的。

周末愉快。

Answer 1

下面是它最后的样子：

@Entity()
class Invitation {
  @PrimaryGeneratedColumn("uuid")
  id: string;

  @Column({})
  projectID: string;

  @Column({})
  otherInformations: string;

  // Relations
  @ManyToOne(() => User, (user) => user.invitations)
  user: User;

  @ManyToOne(() => Project, (project) => project.invitations)
  project: Project;

  @ManyToOne(() => User, (user) => user.invited)
  invitedById: User;
}

@Entity()
class Project {
  @PrimaryGeneratedColumn("uuid")
  id: string;

  @Column({})
  name: string;

  @OneToMany(() => Invitation, (invitation) => invitation.project)
  invitations: Invitation[];
}

@Entity()
class User {
  @PrimaryGeneratedColumn("uuid")
  id: string;

  @Column({})
  name: string;

  @OneToMany(() => Invitation, (invitation) => invitation.user)
  invitations: Invitation[];

  @OneToMany(() => Invitation, (invitation) => invitation.invitedById)
  invited: Invitation[];
}

我正在尝试解释它，但要获得关于关系的更清楚的解释，您可以观看以下视频：https://www.youtube.com/watch?v=8kZ7W-bI5qQ&t=239s&ab_channel=BenAwad (忽略graphql部分)或阅读以下关于关系的文档：https://typeorm.io/#/relations

因此，您的邀请实体是用户和项目之间的多对多关系。您可以通过@ManyToOne()装饰器访问用户，这将在多个用户和一个邀请之间创建一个关系。与您的项目实体相同：

  // Invitation.ts
  @ManyToOne(() => User, (user) => user.invitations)
  user: User;

  @ManyToOne(() => Project, (project) => project.invitations)
  project: Project;

在每个实体中，将相反的关系添加到邀请实体

  // User.ts
  @OneToMany(() => Invitation, (invitation) => invitation.user)
  invitations: Invitation[];

  @OneToMany(() => Invitation, (invitation) => invitation.invitedById)
  invited: Invitation[];

  // Project.ts
  @OneToMany(() => Invitation, (invitation) => invitation.project)
  invitations: Invitation[];

注意，我们在这里使用了[]，因为它是一个...ToMany()关系

invitedById的添加方式与此相同：

  // Invitation.ts
  @ManyToOne(() => User, (user) => user.invited)
  invitedById: User;

  // User.ts
  @OneToMany(() => Invitation, (invitation) => invitation.invitedById)
  invited: Invitation[];