Firebase Cloud Firestore Social network database design

Question

I have a simple question. I am building a Instagram clone app and I want to show each user to their friends. Also they can see the friends list. I am using cloud firestore approach. However I'm a little bit confused about how to store user's friends data? . Should I create a new collection as friendsList

or should I hold the data in users collection as a friends array ?

In the first approach I will create the user data again when some user adds a new friend. Am a new for both firestore and NoSql I would be thankful If anyone can explain.

Answer 1

I'm not going to "answer" as such, but explain the philosophy of NoSQL a bit. The best approach is to design your queries first (i.e. what do you want to get from the database), then design your database schema to make getting the results of those queries efficient and affordable. There are many ways to organize data; you want to take advantage of NoSQL "schema-less" to make your schema match your needs, not the other way around.

Other things to keep in mind: DRY is less critical to NoSQL. Static data (i.e. never or rarely changes) can be stored in multiple places (i.e. a friend's name might be in their profile and in a friends-list) if that saves reads & writes (which are the biggest factor in costs).

So how to organize your database? I don't know; what do you want your database to do?

Answer 2

I should read to this tutorial.This tutorial about is MySql but not important for me if you understand this tutorial you can apply firebase.

I leave a tip below.