Question

I have an application which handles the creation of different shop entities.

The process:
1. User registers to the website
2. User creates a shop (with various attributes)

What I have so far for database tables is:

[USER]  
user_id

[USER_TO_SHOP]  
user_id  
shop_id

[SHOP]  
shop_id

The above design covers the need for 1 user to have many shop entities under their account.
What I want to achieve now, is to have shop entities which are standalone but also have shop entities which are a part of group of shops

Chain of Shops example:
McDonalds Address X Chicago
McDonalds Address X New York
McDonalds Address X Boston

How should I proceed with my database design in order to support chain of shops but also standalone ones? Best practices are really appreciated!

*by standalone I mean a shop entity that does not belong to a chain

Answer 1

From what you’re saying, a shop can belong to between 0 and 1 chains? If so, I would simply add one extra table and add a foreign key to the shop table:

[CHAIN]
chain_id
chain_name

[SHOP]
shop_id
chain_id