Well here's a gotcha everybody should know about. A few days ago I added a column to the main table in the mysql database. A user called the next day and pointed out that she could no longer add entries. I poked around and found that the primary key on the main table no longer had it's autoincrement attribute set. Google searches indicated that this has happened to others and that one had to be very careful when making mods to the table structure. The fix was to drop the auto inc column and add it again. It's a good thing that particular column was not used in a foreing key relationship. So the moral of this one for me is to BE CAREFUL and KEEP A BACKUP.
Speaking of which, in the process of fixing this problem I came across SQLyog. It's a good gui tool for managing a mysql database. In particular it allows you to easily build triggers and stored procedures. So far it's the best tool I have found.
