Many2Many assigns join table's id to related model's id field

[nkovacs]

type User struct {
    Id int64
    Name string
    Languages []Language `gorm:"many2many:user_languages"`
}

type Language struct {
    Id int64
    Name string
}

user_languages table contains three fields: id (primary key), user_id and language_id (foreign keys)

If I do

var languages []Language

db.Debug().Model(user).Related(&languages, "Languages")

the Id field of the Language structs in the languages array will be id the field from the user_languages table, not the id field of the language in the languages table.

The workaround is to add .Select("languages.*"). I did not test this with Preload though.

[jinzhu]

Hi @nkovacs

Thank you for your report, the join table is created manually by yourself?

[nkovacs]

Yes

[LiranCohen]

I used Association() for relationship when looking for 1 which works fine with many2many.

Preload works great with one2many relationships, but I'm getting a "not supported relation" error with many2many Preload.

Wonder if this is the same issue.

[djboris9]

querying an many2many realation also fails if one of the primary keys is not named "ID". Could you please provide an working example with preloading of an many2many relation as a Gist or playground snippet?

[jinzhu]

Hi @nkovacs

The issue for Related should been fixed for a while, and just pushed a commit to fix the issue with Preload

Thank you.