[fw-general] Zend_Session_SaveHandler_DbTable

[Arthur M. Kang]

http://framework.zend.com/manual/en/zend.session.savehandler.dbtable.html
Shows example for Basic Setup and Multi-Column Primary Key.

Can anyone explain the benefits of using the multi-column primary key 
method with the fields specified in the example?  Are there other fields 
that could be inserted to further utilize Sessions?

Arthur