Understanding Firebase data binding with user identifiers - ios

Question

Guys I am trying to learn Firebase framework and I do have question about storing data, so as I understood, the data is stored as entire JSON file in the Firebase database.
Let's say I have few data models (just to simplify my description):
Users and Articles
Using Firebase SDK we can simple create user using very simple query. The Firebase user has uid which I can use for my purposes. My general question right now is how to bind uid with my data.
Correct me if I am wrong but I plan to use uid retrieved from the Firebase to create few nodes in Realtime DataBase like these:
{
"users": {
"$uid": {
"name": "Alex",
"lastname": "Matrosov"
},
"$uid": {
"name": "John",
"lastname": "Malkovich"
}
}
}
So when I create/sign in user I plan to add related info to the users/user node.
Then I want to store user article
{
"articles": {
"$article_id": {
"name": "Some name",
"$uid": "32431kjkjfj232"
},
"$article_id": {
"name": "Some name",
"$uid": "5555fffflllll"
}
}
}
So as I understood right when I will request articles it will contain all articles? Let me know if I am on right way with understanding of this uid and data binding.

Answer 1

Well, I'd say you're almost right. Just a few notes:
Inside article's JSON structure, since the '$' dollar mark on '$uid' field, usually, refers to a variable on firebase's database, I'd recommend you to change it to something else like 'userUID' or anything you want. Leaving the structure to something like this:
{
"articles": {
"$article_id": {
"name": "Some name",
"userUID": "32431kjkjfj232"
},
"$article_id": {
"name": "Some name",
"userUID": "5555fffflllll"
}
}
}
Then, you just query them as follow:
Using Swift 4 and Firebase 4:
let articlesRef = Database.database().reference(withPath: "articles")
articlesRef.observe(.value) { snapshot in
// Snopshot will contain all articles on your db reference.
print(snapshot)
}
let userUID = "..."
let articlesByUser = articlesRef.queryOrdered(byChild: "userUID").queryEqual(toValue: userUID)
articlesByUser.observe(.value) { snapshot in
// In this case, snapshot will contain all articles that has the 'userUID' key equal to what you've passed (what in this case, is the value of userUID constant.)
print(snapshot)
}