我可以用this case部分解决此问题
不幸的是,Preload()函数似乎无法在相关对象集中进一步深入研究。
为了澄清,我有以下模型:
type Room struct {
gorm.Model
Name string
Games []Game `gorm:"ForeignKey:RoomID"`
}
type Game struct {
gorm.Model
RoomID int `gorm:"index"`
Players []Player `gorm:"ForeignKey:GameID"`
}
type Player struct {
gorm.Model
Name string
GameID int `gorm:"index"`
}
当我使用创建的新Room,Game和Player对象创建新对象时,我得到以下数据返回(JSON编码):
{"Value":{"ID":26,"CreatedAt":"2016-05-15T01:21:22.426234189-07:00","UpdatedAt":"2016-05-15T01:21:22.426234189-07:00","DeletedAt":null,"Name":"foo","Games":[{"ID":17,"CreatedAt":"2016-05-15T01:21:22.427026134-07:00","UpdatedAt":"2016-05-15T01:21:22.427026134-07:00","DeletedAt":null,"RoomID":26,"Turns":null,"Players":[{"ID":4,"CreatedAt":"2016-05-15T01:21:22.427560561-07:00","UpdatedAt":"2016-05-15T01:21:22.427560561-07:00","DeletedAt":null,"Name":"TestPlayer","GameID":17}],"Counter":1,"Assigned":false}],"Testing":false},"Error":null,"RowsAffected":1}
但是,如果我尝试使用preload()函数查询结构,则会得到以下信息:
{"Value":{"ID":26,"CreatedAt":"2016-05-15T01:21:22.426234189-07:00","UpdatedAt":"2016-05-15T01:21:22.426234189-07:00","DeletedAt":null,"Name":"foo","Games":[{"ID":17,"CreatedAt":"2016-05-15T01:21:22.427026134-07:00","UpdatedAt":"2016-05-15T01:21:22.427026134-07:00","DeletedAt":null,"RoomID":26,"Turns":null,"Players":null,"Counter":1,"Assigned":false}],"Testing":false},"Error":null,"RowsAffected":1}
请注意,“播放器”部分现在为空。这是我的房间注册和房间查询功能:
func RegisterRoom(w http.ResponseWriter, r *http.Request) {
err := r.ParseForm()
if err != nil {
// Handle error
}
// r.PostForm is a map of our POST form values
room := Room{
Name: r.PostFormValue("label"),
Games: []Game{{
Counter: 1,
Players: []Player{{Name: r.PostFormValue("username")}},
}},
}
t := db.Create(&room)
if err := json.NewEncoder(w).Encode(t); err != nil {
panic(err)
}
}
func RoomShow(w http.ResponseWriter, r *http.Request) {
var rm Room
vars := mux.Vars(r)
roomId := vars["roomId"]
id, _ := strconv.Atoi(roomId)
room := db.Preload("Games").First(&rm, id)
result := db.Find(&room)
json.NewEncoder(w).Encode(result)
}
最佳答案
解决了!答案在Nested Preloading额头下