Fetch particular fields from Firebase database

Question

I am working on firebase project, where i stored user info within a Table. Now my requirement is to show all user's in a Table. Here is my database snapshot

I can fetch all user's with from database using

       if let user = FIRAuth.auth()?.currentUser {
            self.ref?.child("Users").observeSingleEvent(of: .value, with: { (snapshot) in
                // Get user value
                let value = snapshot.value as? NSDictionary
                let name = value?["name"] as? String ?? ""
                let email = value?["email"] as? String ?? ""


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

Above code return me users array with bod, email, name, gender. But i want to fetch only email and name of users. Is there a way to fetch only specified fields from Database ?

Rohan Stark Rohan Stark · Accepted Answer · 2017-07-05T08:18:48

When you read a node, you'll have to retrieve its entire content. So, there is no way to fetch only specific fields from the data returned on reading a path.

Having said that, if it's possible for your use case, I would suggest you to denormalise data with the purpose of queries that only retrieve the information that you need.

For doing that, you can have a separate node that can be called something like Users-NameandEmailList. Now, in this table, have user uids as your child keys, and each entry shall have only a an email and name field.

Something like this :-

Users-NameandEmailList :{

       user1key :{
             name : "ABC"
             email : "[email protected]"
                 },
       user2key : {..},

                        }

I agree that this could lead to replication of data, but if you want to minimise download redundancy and optimise for speed, then this is the way to go!

Fetch particular fields from Firebase database

1 Answers