I have some argued with contractor about Primary key and Unique index + Not NULL. Contractor said Primary Key = (field specify NOT NLL and create unique index ..). I rember some documents say Primary Key and (unique index, not null) still some different. Does anyone have opinion? Thanks. __________________________________ Do you Yahoo!? Yahoo! Mail - Easier than ever with enhanced search. Learn more. http://info.mail.yahoo.com/mail_250 -- //www.freelists.org/webpage/oracle-l