Hi Priya,
Normally you would use the native Logos driver with DIAdem's built-in features to load data from a Citadel data base, rather than Citadel's ODBC interface. But of course, if you really do want to run queries or insert records, then this is not possible with the Logos API, so your only choice is to treat the Citadel data base as a normal SQL data base and use DIAdem's ODBC functions. I haven't personally done this with a Citadel data base, but at the below Discussion Forum you will find a wealth of examples which show how DIAdem interacts with SQL data bases.
http://forums.ni.com/ni/board/message?board.id=60&message.id=2053
Regards,
Brad Turpin
DIAdem Product Support Engineer
National Instruments