Google Firestore - structuring deeply nested ordered data

Question

I\'m trying to figure out how to structure my data for my exercise app with Cloud Firestore. The data model is as follows:

• The app has many sets of exercises

Answer 1

Structure it like below. Basically, each exercise is a document and then put the sub-collections under it. In my case shown below, I do something very similar with "products".

As for ordering, querying, and indexing the data. That should be easy.