Best way to compare input data vs database data
I have a program where the user inputs several bits of information by way of XML. I store the data in a "current" table and a "changes" table (MySQL). The data consists of an EntityID which remains constant along with several other fields. What I need to figure out is the best/most efficient way to check the input data against the data stored in the changes table by EntityID to see if any of the other fields have changed.
Any ideas for how to do this without making a hundred+ queries to the database every time the user inputs some data?