reflect.Value.Set using unaddressable value

Question

g.GET("/", func(c echo.Context) error {
    var users []models.User
    err := db.Find(users).Error
    if err != nil {
        fmt.Println(err)
    }
    return c.JSON(http.StatusOK, users)
})

this is the code for getting and displaying users from table using slice is resulting following error from gorm

reflect.Value.Set using unaddressable value

This is more generic thatn `go-gorm`. `go-yaml`'s `Unmarshal` suffers the same issue when you pass it something that's not properly ampersanded. (Not the technical term, but it is what it is) — meh, May 29 '19 at 22:26

score 71 · Answer 1 · answered Aug 22 '17 at 07:12

71

You have to call Find with a pointer to the slice.

err := db.Find(&users).Error

relevant Gorm documentation: http://jinzhu.me/gorm/crud.html#query

answered Aug 22 '17 at 07:12

S. Diego

876
6
6

then i got a nil reference error i solved it by including driver – Krishna Satya Aug 22 '17 at 07:21
and create users slice before: users = make([]models.User,0) – Oleg Aug 22 '17 at 08:15

score 24 · Answer 2 · answered May 07 '18 at 16:35

24

Just to add clarification to S.Diego answers, changing this:

err := db.Find(users).Error

to this:

err := db.Find(&users).Error

the error says, the variable users is not addressable, because it is not a pointer.

answered May 07 '18 at 16:35

Felipe Valdes

1,998
15
26

score 9 · Answer 3 · answered Aug 04 '18 at 08:55

In a very similar fashion to the accepted answer (but in a slightly different context), and an error that I keep making in different projects:

func migrate(db *gorm.DB) {
    db.AutoMigrate(User{}, Activity{})
}

becomes

func migrate(db *gorm.DB) {
    db.AutoMigrate(&User{}, &Activity{})
}

Notice the ampersands.

reflect.Value.Set using unaddressable value

3 Answers3

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