On Thu, 2005-06-09 at 11:45 -0600, Steve Dibb wrote: > I'm working on creating a new table in our database, and I'm wondering > -- why bother with the possibility of NULL values in a field? It seems > like it always adds more work then its worth. > > What's the benefit of adding the option of IS NULL when you usually have > to check to see if its also blank (field = '' OR field IS NULL)?
You've now seen the greatest flaw in SQL databases. Clearly there are definitely times that you need NULLs, because of the limitations of SQL relational theory. The truth is SQL database really do violate several laws of relational database theory. The presence of the NULL really means that relational algebra isn't quite "pure" in SQL. This is a tradeoff that some pundits really harp on. Of course going to the other extreme (like XML "databases") has problems too. I believe that the use of NULLS can be minimized with careful database normalization. > > Steve > .===================================. > | This has been a P.L.U.G. mailing. | > | Don't Fear the Penguin. | > | IRC: #utah at irc.freenode.net | > `===================================' -- .===================================. | This has been a P.L.U.G. mailing. | | Don't Fear the Penguin. | | IRC: #utah at irc.freenode.net | `==================================='
