t.Fatalf("birthday's precision should be 2, but got %v", precision)
			}
		}
	}

	type UserMigrateColumn3 struct {
		ID                  uint
		Name                string    `gorm:"size:256"`
		Salary              float64   `gorm:"precision:3"`
		Birthday            time.Time `gorm:"precision:3"`
		NameIgnoreMigration string    `gorm:"size:128;-:migration"`
	}

		return json.Unmarshal([]byte(value), l)
	case []byte:
		return json.Unmarshal(value, l)
	default:
		return errors.New("not supported")
	}
}

type Role struct {
	Name string `gorm:"size:256"`
}

func (role *Role) Scan(value interface{}) error {
	if b, ok := value.([]uint8); ok {
		role.Name = string(b)
	} else {
		role.Name = value.(string)
	}
	return nil
}

	Pets []AssociationEmptyPet
}

type AssociationEmptyPet struct {
	AssociationEmptyUserID *uint  `gorm:"uniqueIndex:uniq_user_id_name"`
	Name                   string `gorm:"uniqueIndex:uniq_user_id_name;size:256"`
}

func TestAssociationEmptyPrimaryKey(t *testing.T) {
	if DB.Dialector.Name() != "mysql" {
		t.Skip()
	}
	DB.Migrator().DropTable(&AssociationEmptyUser{}, &AssociationEmptyPet{})