That's not permissions in the general sense of authorisation, that should just be modelled as any other "business logic". Put that article_limit in the users table and join it in the selects.

Edit: or tracking the users article views with timestamps, and making a select aggregate over the month..

> "customer Y cannot insert any more orders if total outstanding/unpaid amount of invoices in last 30 days succeeds Z"

insert into orders select from user a inner join invoices b etc.. any kind of limitless complexity here on how you want to limit the orders.

But you can still implement this easily in queries, so for example granting the client only read permissions, plus execution permissions on certain database functions, and inside these functions you can implement the constraints.

What I'm trying to say, is that you don't necessarily need any backend "services" java etc, to implement these type of constraints, they can be modelled as any other business logic in the database.