Exporting the database? But then I would still have a lot of rows in the database. What I was trying to say is that I archive the "old" records in the database and still have the currently used ones available. How do you go about this?

What is your criteria for a record being "old"? Once you've established your criteria, just archive the database as it is now and then drop the rows that match your oldness criteria.

I imagine that I have also to query down to the dependent tables?