Database dilemma

I was trying to get a list of the plate blocks I needed out of my database yesterday, and was surprisingly frustrated at how hard it was. The problem is that there are a lot of stamps that don't have plate blocks, and there was no easy way for me to tell which entries should have a plate block, but don't, and which just don't come in a plate block variety. For example, Scott #16 is the Tabul mini-sheet. There is no plate block possible for this issue. This called for me to add some new code to my program, and create a new table, the list of stamps without plate blocks. I now have the database check this list when it creates my plate block want list, and if the stamp is on the exclusion list, it does not get added to the want list. I then had to manually go through all the items on my want list and decide if they belonged on the exclusion list or not. At the end of the day, my exclusion list is just over 100 entries (mostly souvenir sheets, although there were some regular stamps that just didn't have plate blocks). My want list is now at roughly 150 plate blocks, mostly from 1996-2004. This does not include the specialized definitive plate block want list that is handled separately. I had to handle those a totally different way, but that has been done for a while now.