What are you considering 'user details' ?
If you have a database with users in it, that's basically the row in the Users table, along with everything in the database that has a user_id, which depending on the data you're talking about, might be enough to just set the user_id to `null`, but if unsure and if possible, then cascade delete is the safe choice.
Basically that's nothing that a normal RDBMS doesn't do efficiently already. If you are using a RDBMS, you should have had a sane deletion policy on your foreign keys already.
It gets more complicated with NoSQL databases of course, but you knew already that by using a NoSQL that's essentially technical debt you're postponing. But having worked on many such systems in the past, it's not a tragedy and certainly not something that couldn't be solved in the last 2 years since the GDPR was adopted.
Honestly, GDPR was adopted 2 years ago and people now act all surprised that it came into effect.
thank you for your response. I've been trying to find this in GDPR docs but i can't seem to find a clear definition. Can you link me to the definition if you have it handy by any chance.
I can tell you couple of examples where simple delete from database is not enough.
One example is a analytics pdf report that was sent to management with geo diagram with number of purchases dotsizes/zipcode in a city.
The two things that needed to be developed were systems around rights of erasure & access. Both of these are pretty straight-forward systems -- it's a REST API for getting user details from a system, and deleting user details from the system.
I believe people are making GDPR out to be a much worse than it is.