與查詢接收項目和鍵程

Question

這裏的簡單結構：

$countryCode 
-autoid13 
    -category: vehicles 
-autoid12 
    -category: sport 
-autoid11 
    -category: food 
-autoid10 
    -category: sport 
-autoid9 
    -category: vehicles 
-autoid8 
    -category: food 
-autoid7 
    -category: sport 
-autoid6 
    -category: sport 

我的問題是我怎麼能只獲取項目進行分類：與ID7-ID11項目之間的運動是什麼？ /自動識別密鑰由火力

Answer 1

管理這裏是如何做到這一點

countryCode 
-autoid13 
    -category: vehicles_13 
-autoid12 
    -category: sport_12 
-autoid11 
    -category: food_11 
-autoid10 
    -category: sport_10 
-autoid9 
    -category: vehicles_09 
-autoid8 
    -category: food_08 
-autoid7 
    -category: sport_07 
-autoid6 
    -category: sport_06 

和僞代碼

ref.orderBy("category") 
     .queryStartingAtValue("sport_07") 
     .queryEndingAtValue("sport_11") 

將返回

-autoid7 
    -category: sport_07 
-autoid10 
    -category: sport_10