Correlate BelongTo

[pejman-hkh]

Your Question

Consider we have a Group model, and Group model has UserId and User model has GroupId and UserId too. How can I set User Belong to Group ?

type User struct {
	BaseModel
	Name            string `gorm:"size:255"`
	Email           string `gorm:"type:varchar(100);index:idx_email"`
	Password        string `gorm:"size:255" json:"-"`
	EmailVerifiedAt time.Time
	IsAdmin         bool
	IsMain          bool
	UserID          uint `gorm:"index"`
	GroupID         uint `gorm:"index"`
	Group           Group
}

type Group struct {
	BaseModel
	Title  string `gorm:"size:255"`
	UserId uint   `gorm:"index"`
	User   User   `json:"user"`
}

I go below error in golang compilation:
invalid recursive type Group

The document you expected this should be explained

Expected answer

[gg1229505432]

Your current error is not a bug with the gorm framework, but a basic program compilation error.
When the object is initialized, it will cause a cross-pointer reference, but the referenced object is not fully initialized, so it will cause infinite recursion.

[gg1229505432]

If you want to correlate the two, consider referencing the array of the other struct in the current struct
type User struct {
BaseModel
UserID uint gorm:"index"
GroupID uint gorm:"index"
Groups []Group json:"groups"
}

type Group struct {
BaseModel
UserId uint gorm:"index"
Users []User json:"users"
}

The sample you can refer to :
#6943 (comment)

[pejman-hkh]

I know that is compilation error. in my case User model is belong to Group and Group model is belong to User and I don't have array and your answer is not the solution.

[gg1229505432]

Groups[0] is Groups

[pejman-hkh]

Let me check it

[pejman-hkh]

It returns empty array
I also set preload Preload("Users")

[gg1229505432]

please give me code sample, I'm at work right now and don't have much time to solve your problem, I will response you later 😅

[pejman-hkh]

thank you a lot for your response and happy for you that have a job :D
my project link:

https://github.com/pejman-hkh/gorn/blob/main/api/app/model/group.go

[gg1229505432]

checkout this:
pejman-hkh/gorn#1

[pejman-hkh]

Let me describe better my problem.
My group has a user creator that created it or I have a User that another user created it, How can get this User in belong to and preload. I don't need users of one group ! I just want user that is belong to userid column on same table.

[pejman-hkh]

I solved this problem with made another package name with same model name with required fields. with helper model I can fetch each fields that I require.

If Gorm let us to define Table Name in struct we can fetch each fields we require with define struct on same place :

type Group struct {
	Title       string       `gorm:"size:255" json:"title"`
	UserId      uint         `gorm:"index" json:"user_id"`
	User struct {
		Table string `gorm:"table:users"`
		ID        uint
		Name      string
	}
}

[gg1229505432]

@jinzhu you can close this issues