如何检查Firebase数据库值是否存在? [英] How do I check if a firebase database value exists?
问题描述
我将实时数据库与Google的Firebase一起使用,并试图检查是否存在小孩。
我的数据库结构如下
$ $ p $ code $ - $($) / jake /
- / rooms /
- / room1 /
---(房间1属性)
- / room2 /
---(room 2房产)
我想查看room1是否存在。
我尝试了以下方法:
让roomName:String =room1
roomsDB.child房间名称).observeSingleEventOfType(.Value){
(snap:FIRDataSnapshot)in
let roomExists:Bool = snap.value!= nil? 取:不取
}
访问 snap.value
它会返回该房间属性的JSON,但是如何检查房间( / rooms / room1 /
)是否为那么开始吧?
评论是否需要澄清
<$参考()
$ b ref.child(rooms)。observeSingleEventOfType(.Value,withBlock :{(快照)在
如果snapshot.hasChild(room1){
print(存在的真实房间)
} else {
print(false room does not exist)
}
})
I'm using the Realtime Database with Google's Firebase, and I'm trying to check if a child exists.
My database is structured as the following
- / (root)
- /users/
–- /james/
-- /jake/
- /rooms/
-- /room1/
--- (room 1 properties)
-- /room2/
--- (room 2 properties)
I would like to check if room1 exists. I have tried the following:
let roomName:String = "room1"
roomsDB.child(roomName).observeSingleEventOfType(.Value) {
(snap:FIRDataSnapshot) in
let roomExists:Bool = snap.value != nil ? "TAKEN" : "NOT TAKEN"
}
In accessing snap.value
it returns a JSON of the properties of that room, but how would I check if the room (/rooms/room1/
) is there to begin with?
Comment if any clarification is needed
self.ref = FIRDatabase.database().reference()
ref.child("rooms").observeSingleEventOfType(.Value, withBlock: { (snapshot) in
if snapshot.hasChild("room1"){
print("true rooms exist")
}else{
print("false room doesn't exist")
}
})
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