Hello,
normally you can use IS NULL - means
SELECT * FROM table WHERE field IS NULL
or in procedures
IF(var IS NULL) THEN
But this depends on the database and the language that you use. Please give me hint which database you ar using.
You are developing an adminstration software for relational databases. Can I see your work ? I am very interested in such programs
Regards
Manfred Peter
(Alligator Company)
http://www.alligatorsql.com