sql - 如何在gorm中创建双向多对多关系

Question

根据the doc的自相关many2many如下

type User struct {
  gorm.Model
  Friends []*User `gorm:"many2many:user_friends"`
}

但我希望能够建模如下:

type User struct {
  gorm.Model
  Followings []*User `gorm:"many2many:user_relation"`
  Followers []*User `gorm:"many2many:user_relation"`
}

因此，以下过程运行良好。如果userA跟在userB之后，则userB可以在其关注者中看到userA。

Answer 1

我可以通过以下标签实现它:

type User struct {
  gorm.Model
  Followings []*User `gorm:"many2many:user_relation;foreignKey:ID;joinForeignKey:UserA;References:ID;joinReferences:UserB"`
  Followers []*User `gorm:"many2many:user_relation;foreignKey:ID;joinForeignKey:UserB;References:ID;joinReferences:UserA"`
}