How to update particular value of child in Firebase DB

Question

I am following this document. Following is my code for update:

func updateDealResultToServer(key:String,dealResult : String)
{

    let post = ["dealResul": dealResult]
    let childUpdates =
        ["/komal_xyz/\(key)": post
        ]

    rootRef.updateChildValues(childUpdates)

}

This Is my Firebase database structure:

I want to only change the value for dealResult. Whenever I try to run above code for particular child node like 1473670100726, other value except dealResul is deleted.

Answer 1

For Updating values at a particular node in Firebase Realtime Database, use:-

• You can either use runTransactionBlock:

    func updateTotalNoOfPost(completionBlock : (() -> Void)){
  
  
  let prntRef = FIRDatabase.database().reference().child("komal_kyz").child(your_AuroID).child("dealResul")
  
  prntRef.runTransactionBlock({ (resul) -> FIRTransactionResult in
      if let dealResul_Initial = resul.value as? Int{
  
          //resul.value = dealResul_Initial + 1
          //Or HowSoEver you want to update your dealResul. 
           return FIRTransactionResult.successWithValue(resul)
      }else{
  
          return FIRTransactionResult.successWithValue(resul)
  
      }
      }, andCompletionBlock: {(error,completion,snap) in
  
              print(error?.localizedDescription)
              print(completion)
              print(snap)
          if !completion {
  
             print("Couldn't Update the node")
          }else{
  
              completionBlock()
          }
      })
  
   }
  

  While calling this function:-

  updateTotalNoOfPost{
         print("Updated")
        }
  

• Or just call updateValues

      let prntRef  = FIRDatabase.database().reference().child("komal_kyz").child(your_AuroID)
      prntRef.updateChildValues(["dealResul":dealResult]) 
  

PS:- Prefer using runTransactionBlock: instead of .updateChildValues if you only want to increment a particular node. Also read this: -https://stackoverflow.com/a/39458044/6297658

Answer 2

I suggest using setValue for single child updates (keep in mind that I am using Swift 3, slight syntax changes may apply but you should be fine):

rootRef.child("komal_kyz").child(key).setValue(["dealResul":dealResult])