Is it possible to have unique constraint on parameters of an event? I will have a number of users using my Dapp, and I have provided functionality to delete the users. So while reading from the transaction log, I will get a list of all the users created to date. I want only the users that are active on my Dapp.
To get the active set users you need to combine the transaction logs of
All created users - All deleted users
Or considering storing your users in EnumerableSet and you can directly query the active users using smart contract calls, instead of events.