firebase-database Reading data Understanding which data referenced by getReference()

Example

In this example, we use this database:

"your-project-name" : {
    "users" : {
        "randomUserId1" : {
            "display-name" : "John Doe",
            "gender" : "male"
        }
        "randomUserId2" : {
            "display-name" : "Jane Dae",
            "gender" : "female"
        }
    },
    "books" {
        "bookId1" : {
            "title" : "Adventure of Someone"
        },
        "bookId1" : {
            "title" : "Harry Potter"
        },
        "bookId1" : {
            "title" : "Game of Throne"
        }
    }
}

If you use above database then:

• FirebaseDatabase.getInstance().getReference()

  will point at your project's parent, "your-project-name" data. So the dataSnapshot you acquired will contain all of data inside it, including all of "users" data and "books" data.

• FirebaseDatabase.getInstance().getReference("users") and FirebaseDatabase.getInstance().getReference().child("users")

  will have the same result, pointing at "your-project-name/users"

• FirebaseDatabase.getInstance().getReference("users/randomUserId1") and FirebaseDatabase.getInstance().getReference().child("users/randomUserId1") and FirebaseDatabase.getInstance().getReference().child("users").child("randomUserId1")

  will have the same result, pointing at "your-project-name/users/randomUserId1"

Note: this example is needed to fully understand which data is inside dataSnapshot object