Class update detection

[Axium Computer Services]

I have a relational database that has several tables each more or less 
translating to a python class and the fields of each table translating 
into attributes of the python class.  I have no problem creating an 
instance of the class, running a query and filling the attributes.  Then 
this information will be accessible from a UI.  The problem I am running 
into is when the user is done working in the UI I need to determine if 
any of the class attributes have been changed to I can issue an update 
query to the database with the changes.  Is there a generally accepted 
method to do this?   Is there some way to create a checksum of the class 
attributes?

Any help would be much appreciated.

Thanks

Steven Potter