Complicated connections between TypeORM and MySQL

Question

Complicated connections between TypeORM and MySQL

Currently leveraging TypeORM in tandem with MySQL, my database comprises of two main Entities, namely User and Project:

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

    @Column({})
    name: string;
}

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

    @Column({})
    name: string;
}

In the near future, I aim to introduce a third Entity called Invitation. Each invitation is uniquely identified by the userId and projectId pair. Although a user can receive invites for multiple projects, they should only have one invite per project. Additionally, I intend to record the user responsible for sending out the invitation.

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

    @Column({})
    userID: string;

    @Column({})
    invitedById: string;

    @Column({})
    projectID: string;

    @Column({})
    otherInformations: string;

}

I am seeking advice on how to properly establish these relationships using TypeORM's Relation decorators. Any guidance would be greatly appreciated as I am relatively new to the realm of ORM development.

Wishing you all an enjoyable end to your weekend.

mysql typescript nestjs typeorm

Answer 1

Answer №1

Here is the final representation:

@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[];
}

I am attempting to clarify it, but for a more concise explanation of the relationships, you can refer to this video tutorial: https://www.youtube.com/watch?v=8kZ7W-bI5qQ&t=239s&ab_channel=BenAwad (please disregard the graphql section) or read the relation documentation here:

Hence, your Invitation entity serves as the bridge between the User and the Project in a many-to-many relationship. The user can be accessed via the @ManyToOne() decorator, establishing a link between multiple users and a single invitation. The same methodology applies to the Project entity:

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

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

In each Entity, ensure to incorporate the corresponding relationship with the Invitation entity

  // 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[];

Note the use of [] due to it being a ...ToMany() relationship

invitedById should also be added similarly:

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

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

Answer 2

Here is the final representation:

@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[];
}

I am attempting to clarify it, but for a more concise explanation of the relationships, you can refer to this video tutorial: https://www.youtube.com/watch?v=8kZ7W-bI5qQ&t=239s&ab_channel=BenAwad (please disregard the graphql section) or read the relation documentation here:

Hence, your Invitation entity serves as the bridge between the User and the Project in a many-to-many relationship. The user can be accessed via the @ManyToOne() decorator, establishing a link between multiple users and a single invitation. The same methodology applies to the Project entity:

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

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

In each Entity, ensure to incorporate the corresponding relationship with the Invitation entity

  // 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[];

Note the use of [] due to it being a ...ToMany() relationship

invitedById should also be added similarly:

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

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

Complicated connections between TypeORM and MySQL

Answer №1

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