Get Firebase data ordered by value

Question

Is there any way to get a certain number of Firebase data entries based on value. For example, if a certain entry had 100 children, each with a number value, would there be any way to request the children with the ten highest values?

EDIT: I realize that I could simply request the parent and iterate through the entire hierarchy of data until I find the ten with the largest value, but this would be a waste of user's data, especially if the parent contained thousands of children.

Answer 1

With firebase you are dealing with a nosql database. When using a nosql database, generate your reports when you write the data, not when you read it.

eg. For the case you mentioned, maintain another object that always contains the top ten records (or pointers to them).

Every time you write a record to the database check with the top ten list, if the record belongs there too, in which case do what is necessary.

This approach is faster and more efficient than iterating through a database.