typeorm - 如何向“多对多”表添加额外字段？

Question

例如：

3桌

user
user_business_lines_business_line
business_line

那些由typeorm声明创建的User

@ManyToMany(type => BusinessLine)
@JoinTable()
businessLines: BusinessLine[]

然后，如何添加列字段，如

@CreateDateColumn({ type: 'timestamp' })
createdAt: Date

@UpdateDateColumn({ type: 'timestamp' })
updatedAt: Date

到 user_business_lines_business_line

Answer 1

无法在自动创建的多对多桥表中添加自定义列。所以创建另一个表并在它们之间给出一对多和多对一的关系。

例如：

三桌

用户 -> 表 1

业务线 -> 表 2

UserBusinessLine -> User 表和 BusinessLine 表之间的桥接表

UserBusinessLine table will contain the foreign key of both parent tables and also we can add custom culomns into it.

在用户表中

@OneToMany(() => UserBusinessLine, (userBusinessLine) => userBusinessLine.user)
public userBusinessLines: UserBusinessLine[];

在业务线表中

@OneToMany(() => UserBusinessLine, (userBusinessLine) => userBusinessLine.businessLine)
public userBusinessLines: UserBusinessLine[];

在 UserBusinessLine 表中

@ManyToOne(() => User, (user) => user.userBusinessLines)
public user: User;

@ManyToOne(() => User, (businessLine) => businessLine.userBusinessLines)
public businessLine: BusinessLine;

// Custom Colums
@CreateDateColumn({ type: 'timestamp' })
createdAt: Date;

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

所以现在自定义表有 User 表和 BusinessLine 表的外键。还有 CreateddateColumn 和 UpdatedDateColumn

Answer 2

您可以为 ManyToMany 关系指定自定义连接表

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id: number

  @Column()
  name: string

  @ManyToMany(type => BusinessLine, businessLine => businessLine.users)
  @JoinTable({
    name: 'user_business_line',
    joinColumn: {
      name: 'userId',
      referencedColumnName: 'id',
    },
    inverseJoinColumn: {
      name: 'businessLineId',
      referencedColumnName: 'id',
    },
  })
  businessLines: BusinessLine[]
}

@Entity('user_business_line')
export class UserBusinessLine {
  @CreateDateColumn({ type: 'timestamp' })
  createdAt: Date

  @UpdateDateColumn({ type: 'timestamp' })
  updatedAt: Date

  @Column()
  @IsNotEmpty()
  @PrimaryColumn()
  userId: number;

  @Column()
  @IsNotEmpty()
  @PrimaryColumn()
  businessLineId: number;
}

@Entity()
export class BusinessLine {
  @PrimaryGeneratedColumn()
  id: number

  @Column()
  name: string

  @ManyToMany(type => User, user => user.businessLines)
  users: User[]
}