How to structure properly Firebase Database?

Question

I read some Firebase database structure guides on how to structure your data properly (without data nesting) but I have one question. So, I have an iOS app that uses Firebase database. The users need to login/register. In terms of data structure, my database looks like this:

-Database
---Users
-----User1
--------username: johndoe
---------email: johndoe@test.com
---------display_name: John Doe
-----User2 {....}
-----User3 {....}

Now, let's imagine I have 100K users in there. Every time a new user is being registered, I check if the username & the email already exist in the database, if they don't then create the new user account.

My question is - Do I need to create a new object that contains only the usernames and another that contains only the emails? I'm asking this because I'm concerned that if I iterate through the Users objects I will potentially be downloading hundreds of megabytes just to check if the username and the email already exist.

Answer 1

Firebase will not allow duplicate users (authentication names). So when you call createUser, firebase will return an error if the user already exists.

Secondly, if you are performing a query for a specific item in Firebase, you are not downloading anything unless that item is found. So whether its 10 or 100k user nodes, nothing is downloaded when performing a query other than the nodes that match the query, which would only be one if there was a duplicate user. again though, this is not needed since Firebase rejects duplicate authentication names.

And to clarify; there is nothing wrong with nesting nodes. However, keeping them flat is usually better depending on your use case . So don't go overcomplicating your structure if you don't need to.

Oh, and your Firebase structure is spot on. Keep going with that.