Firebase query help for react-native

Question

I'm kinda new to firebase & react-native but I need a little help with a query I have to do for my project.

So let's say I have 2 tables

Posts:{postID(key), posterID, description}
Likes:{likeID(key), postID, likerID}

so the relationship between these two tables is on postID

Is there a way to count all likes for each Post and return top 10 with most likes? I know that this process can't be all on server side so I'm fine with any solutions really.

I think this is the query to count likes for one post:

firebase.database().ref(`/likes`)
        .orderByChild('postId').equalTo(postID)
        .once('value', snapshot => {
            const likesCount = snapshot.count;

        })

if you need any sort of complex queries, I would strongly recommend not using firebase, as you'll be building workarounds all day long — Kai, Jan 30 '19 at 05:22

score 1 · Answer 1 · answered Jan 29 '19 at 23:38

Is there a way to count all likes for each Post...?

Firebase has no built-in aggregation queries. You'll typically either do this client-side, or through Cloud Functions, and write the count into each post. You'd then order on that "count property" to return the posts with the most likes.

Also see:

In Firebase, is there a way to get the number of children of a node without loading all the node data? (showing how to atomically increment a counter)
this sample of counting child nodes using Cloud Functions
Is the way the Firebase database quickstart handles counts secure? (a discussion about securely counting likes)
Aggregate values coming from firebase database

Firebase query help for react-native

1 Answers1