There are two types of users, one is free users and the other is paid users. As a user with the FreeUser role, I can only have 3 open (time has not yet ended) activities because PayingUser has no limit. How to manage it in database table
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UserType usertypeid, PK usertype, NN User userid, PK username, NN usertype, FK UserType.usertypeid
You have several options for events.
Regardless, the logic behind activity management is handled by the application.
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