How to get just one child from FIrebase Realtime Database instead of whole list

Question

I am implementing Firebase Realtime Database for my app. The database contains a lot of entries that will continue to grow in the future. I want to retrieve only a specific child from the database, but i can't find any implementation for doing that. In Firebase too the implementation retrieves all the entries from the database. This will be cumbersome in the future. Is there any way to retrieve only specific entries or just one entry(depending upon the customisation)?

Please help.

@ALex Mamo: This is the database image

do you know the correct path of child you want to know the value of? — Aayush Singla, Aug 16 '18 at 21:05
Yeah I know the path of child its just that want to implement search and retrieval of child based on its unique id that Firebase allocates or some unique value pertaining to the child. — Aashay Chaturvedi, Aug 17 '18 at 06:14
@AashayChaturvedi Please add your database structure and indicate which specific elements you want to get. Please also responde with @. — Alex Mamo, Aug 17 '18 at 09:57
@AlexMamo Please ignore the above comment. I have updated the image url of database and the value i want to retrieve is "eerifd" based on its value. — Aashay Chaturvedi, Aug 18 '18 at 09:51
@AashayChaturvedi What do you mean through "retrieve is "eerifd" based on its value"? — Alex Mamo, Aug 19 '18 at 08:37
@AlexMamo I want to search in Firebase Database for the child i want before i download the whole database list. I want to get only few values from database rather than getting the whole list and then picking the child i want. — Aashay Chaturvedi, Aug 19 '18 at 13:46
I understand that and it's correct waht you want to do but what do you mean through "retrieve is "eerifd" based on its value"? — Alex Mamo, Aug 20 '18 at 08:05

score 0 · Answer 1 · answered Aug 16 '18 at 20:50

0

Perhaps you are refering to shallow query, which only read the first child ? In this case you might want to look at the API implementation as mentioned here:

Firebase (2016) Shallow Query

answered Aug 16 '18 at 20:50

Linh

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score 0 · Answer 2 · answered Aug 16 '18 at 22:08

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There are two different ways of getting it. You'll have to change 'messages' to the name of your database. Replace PostTitle with the specific data you're trying to receive.

var rootRef = firebase.database().ref().child("messages");

rootRef.on("child_added", snap=> {

  var postTitle = snap.child("PostTitle").val();

or

exports.sendPushNotification = functions.database.ref('/messages/{id}').onWrite((change, context) => {

    const afterData = change.after.val();
    const postTitle = afterData.PostTitle;

answered Aug 16 '18 at 22:08

Argiator Morimoto

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Does PostTitle suggest that I have fill in the specific unique id of child? or the unique search parameter that will give me one child or a list of child containing that parameter? – Aashay Chaturvedi Aug 17 '18 at 06:17
It should automatically give you the information, If you test it you'll see what I'm saying. – Argiator Morimoto Aug 17 '18 at 16:03
this is javascript code. I need the code for android. Soory but i'm not much acquainted with javascript – Aashay Chaturvedi Aug 19 '18 at 07:11

score 0 · Answer 3 · answered Aug 06 '20 at 12:56

if you want retrieve few records this might help. as per image structure attached.

you can restructure the data, and use set method with keys as 0,1,2.... instead of "LK34h...."->0 . use set method and store latest index value.

you retrive like this

firebase.database().ref().child('users_Post/0').on('value',sn=>{ console.log(sn.val())//use sn.val() })

How to get just one child from FIrebase Realtime Database instead of whole list

3 Answers3