One to One relationship in Firestore

Question

I have a collection of students and another of teachers. Student documents have the teacher ID inside as a field. I want to save only the teacher's ID to avoid that if the teacher updates his information avoid updating each of the students as i would have to do if you had the teacher document inside the student. When I receive the student's data, is there a way to get the teacher's data in a json? In order to avoid making a new query to the teacher collection looking for the teacher ID, I want to send the teacher's id as a fiels but receive the Teacher object associate with that id

Answer 1

You either duplicate the data in both collections, or you perform two queries. There are no alternatives to this - you need to pick a strategy. There are no SQL-like "joins" in Firestore that allow a query to span multiple collections. With NoSQL databases like Firestore, it's typical to duplicate data (called denormalization) to improve query speed.

See:

• What is denormalization in Firebase Cloud Firestore?
• Duplicating data in Firebase Firestore