Re: NULL-Problem, Bug or Feature

>> From uunet!rmy.emory.edu!informix-list-owner Thu Nov 21 02:16:10 1991 >> From: uunet!pdact.pd.necisa.oz.au!ronl (Ron Lees) >> To: informix-list@rmy.emory.edu >> Subject: Re: NULL-Problem, Bug or Feature >> >> Joerg, >> >> What you've described sounds like another example of Informix's ternary logic >> that occurs in using NULL values. It plagues 4GL programmers. "plagues"?? Given the need to support 3-valued logic, what does 4GL do *wrong* in that context? >> If you need to use NULLS it is necessary to code 4GL programs as follows: >> >> if (a <> B) or >> (a IS NOT NULL and b IS NULL) or >> (a IS NULL and b IS NOT NULL) then .... I find this more straightforward to handle inequality-respecting-nulls: if (a = B) then -- nothing else ...desired action... end if >> Ron Lees rlees@pdact.pd.necisa.oz.au >> NEC Information Systems Australia Pty Ltd Voice: +61-6-2516411 >> Software Development Centre (Canberra) Fax: +61-6-2516947 >> PO Box 244, Belconnen ACT 2616, AUSTRALIA -- Alan Denney aland@informix.com {pyramid|uunet}!infmx!aland "Democracy means buying a house you can't afford with money you don't have to impress people you wish were dead." - Carson