来自2个节点的Firebase查询

Question

cards

    cars
    -- idcars
        -- type:
        -- age:
        -- user: iduser

    users
    -- iduser
     -- username
     -- usermail


    ads
    -- iduser
     -- ads1 : idcars
     -- ads2 : idcars

With this structure how it's possible to retrieve all ads for a user together with their own data?

Example:

ads1: 
type: golf
age:2

I'm completely new with Firebase

Answer 1

This should be what you need to get the authenticated user and then you can use this model to just retrieve the whole ads branch filtering through it to have everyones ads detail (if you want)

let userID = FIRAuth.auth()?.currentUser?.uid
ref.child("ads").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in

  // Get user value
  let value = snapshot.value as? NSDictionary // This gets the whole ad branch with all the users ad data
  let adsValue = value?["ads1"] as? String ?? "" // This is the specific value of 'ads1' node

  // ...
  }) { (error) in
    print(error.localizedDescription)
}

Answer 2

Maybe like this,

get the user id then put it in ref.child(yourString)

ref = FIRDatabase.database().reference()
    ref.child("iduser").observeSingleEvent(of: FIRDataEventType.value, with: { (snapshot) in })

Answer 3

This will require two read operations, one for the user and one for their ads. See the Firebase documentation for reading data and for querying lists .

If you're having trouble making this work, post the minimal code that reproduces the problem .