CODEWITHSUNDEEP
databasefirebasegoogle-cloud-firestorenosql
thedeg123
thedeg123

Reputation: 438

Handling Complex Queries in Firestore

I have a database consisting of reviews, follow, and users. Where users following other users is a many to many relationship modeled by the follow table. In total my schema looks as follows:

I want to run a query to get the T most recent reviews where the user is following the author. In a SQL environment I would do this with two joins and a where clause.

Let us consider a user following n people, where each person they're following has m reviews. I was considering finding all reviews for all of the n people one is following, then discarding all those older than T, but recognize the number of reads will be n*m. As we can easily expect n > 100 and m > 1000, this is not a viable solution. I recognize there is probably no great way to do this in firestore. Any suggestions?

UPDATE: The top answer to a similar question is giving an nk (where k is an arbitrary limit) solution for a number of reads. It is also answering an easier question: "get the T most recent reviews for each person one is following" not "get the T most recent reviews of all people one is following." This answer, suggests keeping an updated copy of all followers in every review then doing a whereArrayContains clause to find reviews one is following. But if user A follows a user B who has B_m reviews, we will perform B_m writes for each follow or unfollow. We will also be massively denormalizing our database, storing and updating the same information in thousands of locations.

Upvotes: 1

Views: 332

Answers (2)

neotrix
neotrix

Reputation: 57

there's a way that worked for me which is creating a link between indexes, how is that ? going to firestore => indexes and add index with this you can link the fields you want to query on and then you will be able to do this query in your code

Upvotes: 1

Long Nguyen
Long Nguyen

Reputation: 436

Your data seems highly relational so the best option for you is to switch to a relational database. The only way to get this to work in firestore is to either completely denormalize your data or chain a ton of queries together to get all of the data you need, neither is ideal in my opinion.

Upvotes: 1

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