It is not about DBI - but about converting relations to logic predicates. I know how to get the data from the database (and if you looked at my first post in this thread you would discover that I use an ORM for that - that is order independent), it is the conversion that is the difficult and in my solution order dependent step. I don't want to be rude but I think you did not read the whole thread here and now you attack me with some straw man tactics. It is insulting when you suppose that I don't know basic facts.