I have some issue in custom middleware using on access some data

I am working on this logic using custom middleware. but I am very confused about this. please give me some idea or soluting to Learn form...

Using Custom Middleware

This is my aim to do

• Create Packages Table
• Create Business Table
• User can Subscribes to Packages
• User can Add Project to Business

- The core of my Task:

• Use middleware to check wheater a dependency exists or not
• A User must not be able to add a project if a business does not exist.
• A user must no be able to create a business if there are no subscriptions.
• A user must not able to subscribe package if packages do not exist.

via Chebli Mohamed