Auto increment a value in firebase with javascript

Question

Hello I'm working on some firebase project and i can save my datas via javascript into firebase database. But i couldn't figure it out to auto increment child value (my child value is duyuru, you can see the details in the below) of my database. I'm sharing my code in below can you give me hints to solve this issue.

  <script>

      // Initialize Firebase
      var config = {
        apiKey: "sample1",
        authDomain: "sample2",
        databaseURL: "sample3",
        storageBucket: "sample4",
      };


      firebase.initializeApp(config);
      var database = firebase.database();

     firebase.initializeApp(config);
  var database = firebase.database();

  function writeUserData(userId, name, email, imageUrl) {
  var kategori1 =  document.getElementById("kategori").value;
  var duyuru1 = document.getElementById("duyuru").value;
  var name1 = document.getElementById("name").value;
  var email1 = document.getElementById("email").value;
  var imageUrl1 = document.getElementById("imageUrl").value;





  firebase.database().ref(kategori1 +"/" + duyuru1).set({
    username: name1,
    email: email1,
    profile_picture : imageUrl1
  });
}

    </script>

and the out is like this

{
    "duyuru1": {
        "email": "kjfdlkl",
        "profile_picture": "dsfsd",
        "username": "meraha"
    }
}

I want to output data like;

{
    "duyuru1": {
        "email": "kjfdlkl",
        "profile_picture": "dsfsd",
        "username": "meraha"
    },

    "duyuru2": {
        "email": "kjfdlkl",
        "profile_picture": "dsfsd",
        "username": "meraha"
    }
}

duyuru (child value) section should be auto increment, That's what i wanted for. Thank you for your answers

score 31 · Accepted Answer · edited Sep 26 '17 at 08:16

31

Firebase has no auto-incrementing keys, since those don't work well in massively multi-user systems where clients can be offline for prolonged periods.

Instead, Firebase has its own type of auto-generated keys called push IDs. These push IDs have the same important properties of sequences in many relational databases: they are ordered and sequential. But in addition, they can be calculated client-side, even when the client is not connected to the Firebase servers.

See the Firebase documentation on saving data in lists, this legacy blog post on why arrays don't work well in Firebase and this post on how push ids work.

edited Sep 26 '17 at 08:16

Community

1
1

answered Aug 21 '16 at 15:32

Frank van Puffelen

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Thank you for answering my question. But i wanna ask you something when i use that method it created random keys, I just wondering if there is any way to create custom increment with javascript. Like when users add data increased data automatically. For example for the first post duyuru1, second post duyuru2, etc.. – Esat kemal Ekren Aug 21 '16 at 17:25
That's number at the end seems like an array index and thus won't scale. The links I provided explain the reasons better than I can do here. If you insist on using custom sequences, you'll have to implement them yourself. Firebase has no built-in support for them. – Frank van Puffelen Aug 21 '16 at 21:31
Yes according to link that you gave me its better work with that default property thank you. Your answer give me another look for my app. Have a nice day – Esat kemal Ekren Aug 21 '16 at 21:34

score 2 · Answer 2 · answered Feb 22 '19 at 16:14

Firebase recommends using distributed counters: https://firebase.google.com/docs/firestore/solutions/counters

For the document that requires the counter, you'd initialize a subcollection of, say, 10 documents and run transaction increments on a random shard whenever you need a counter incremented.

Then you'd query the collection of shards and sum their counters.

Ozzy Ozmen Celik · Answer 3 · 2020-02-10T03:20:48.617

There is no AutoId in firebase but here is a quick way to set as auto id

Forexample ;

1- create yourModel ( which one u gonna send as model to firebase )

2- DatabaseReference firebaseDatabase;

3- firebaseDatabase =FirebaseDatabase.instance.reference();

4- firebaseDatabase.child("table_name").push().set( yourModel.toJson() );

Also for getting data u can write code like that

var result= firebaseDatabase.child("table_name").once().then(
   (DataSnapshot datasnapshot){
     Map<dynamic,dynamic> values= datasnapshot.value;
     values.forEach((key,value){
       print("key:"+key+" value:"+value["name"]);
     });
   }
 );
 print(result);

I tried it and works great

Have a nice day !!!

score 2 · Answer 4 · answered Aug 25 '20 at 15:22

IMHO, I think we should use transaction to save increment_id. Please take a look here: https://firebase.google.com/docs/database/web/read-and-write#save_data_as_transactions

function toggleStar(postRef, uid) {
  postRef.transaction(function(post) {
    if (post) {
      if (post.stars && post.stars[uid]) {
        post.starCount--;
        post.stars[uid] = null;
      } else {
        post.starCount++;
        if (!post.stars) {
          post.stars = {};
        }
        post.stars[uid] = true;
      }
    }
    return post;
  });
}

Hüseyin Çakanlı · Answer 5 · 2019-12-05T08:58:46.993

1

You can use for first column key to "USERID + Your_indexNumber(in client var)" etc.

This is very simple method.

Your table must like this:

https://i.stack.imgur.com/k9UI6.png

edited Dec 05 '19 at 08:58

answered Dec 05 '19 at 08:45

Hüseyin Çakanlı

11
5

Auto increment a value in firebase with javascript

5 Answers5

Also for getting data u can write code like that

Linked

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