I'm going to have to disagree--how often do you have a "created_at" field in your data?
Moreover, how useful is it to see when data was collected? You pretty much need that to be able to model user behavior over time.
If the deleted data breaks a report, that's in line with what the user wanted--failing that, you should've used a proper design pattern to transparently fill in the gaps.
Let's not pretend that this would actually be anything other than a minor annoyance.
EDIT:
A program must be written that seeks out timestamped data ready to expire and delete it."
Here, let me help, after one second on Stack Overflow:
DELETE FROM Table WHERE DATEADD(year, 2, CreateDate) < getdate()
There's your program. Anybody want to show how to do this in Cassandra or Mongo? Might as well put that NoSQL map/reduce to work...
Moreover, how useful is it to see when data was collected? You pretty much need that to be able to model user behavior over time.
If the deleted data breaks a report, that's in line with what the user wanted--failing that, you should've used a proper design pattern to transparently fill in the gaps.
Let's not pretend that this would actually be anything other than a minor annoyance.
EDIT:
A program must be written that seeks out timestamped data ready to expire and delete it."
Here, let me help, after one second on Stack Overflow:
There's your program. Anybody want to show how to do this in Cassandra or Mongo? Might as well put that NoSQL map/reduce to work...