Unique inventory database for each separate store

I want to build an app that helps my local stores to post their inventory (image, price, quantity, etc). Each store has a unique database. They should not be able to see other stores or their database. Each store should be able to log in with their unique email/password.

My job is to extract the database and submit it on one website, with local stores and their inventory in our area.

Do I need to create a separate app for each store in my back end? I am going to have up to 20 stores so I rather have one app and switch between stores. Or is it easier just to download the database from the spreadsheet for each individual store? Other selutions?

Thank you.

One app, a user x = x store (using usermail()) and then a security filter on the table with storename.


For reference:


Thank you Steve and Leonardo. Now I know where to start my project.