GORM not saving has-many structs

I have a room entity that has associated members. When I save the room using GORM, only one member gets saved even if the slice has multiple members.

I've overwritten the primary key to be the uuid field and set the foreign keys.

What am I missing?

type Room struct {
	gorm.Model
	UUID     string     `gorm:"uuid;primaryKey"`
	Members  []*Member  `gorm:"foreignkey:uuid"`
}

type Member struct {
	gorm.Model
	UUID     string `gorm:"uuid;primaryKey"`
	RoomUUID string `gorm:"room_uuid"`
	UserUUID string `gorm:"user_uuid"`
	UserRole string `gorm:"user_role"`
}

// only saves one member even if there are more.
func (r *Repo) SaveRoom(room *records.Room) error {
	return r.DB.Transaction(func(tx *gorm.DB) error {
		err := tx.Create(room).Error
		if err != nil {
			return err
		}
		return nil
	})
}

CREATE TABLE rooms (
    id int NOT NULL UNIQUE AUTO_INCREMENT,
    created_at timestamp,
    updated_at timestamp,
    deleted_at timestamp,

    uuid VARCHAR(36) NOT NULL UNIQUE PRIMARY KEY
);

CREATE TABLE members (
    id int NOT NULL UNIQUE AUTO_INCREMENT,
    created_at timestamp,
    updated_at timestamp,
    deleted_at timestamp,

    uuid VARCHAR(36) NOT NULL UNIQUE PRIMARY KEY,
    room_uuid VARCHAR(36) NOT NULL,
    user_uuid VARCHAR(36) NOT NULL,
    user_role VARCHAR(36) NOT NULL 
);

This is because your foreign key association is wrong. This should be gorm:"foreignKey:room_uuid;references:uuid" instead of gorm:"foreignkey:uuid". Additinally you might need to manually delete the wrong foreign key created previously.

Another point is you are using gorm.Model which has an ID field and additionally you are using UUID. My suggestion is to use one primary key instead of two if it's not necessary.