Firebase: Populate a search with data from another collection

Question

I have two collecitons: users and establishments, in the user collection i save the respective establishment id. I would like to know how to bring back the establishment data when i request the users.

Answer 1

Firestore operations always read data from a single collection. They have no concept like SQL's server-side JOIN. If you want to load the establishments, you will have to do so with an additional call, possibly a separate call for each of them.