On Thu, Apr 16, 2015 at 11:48 AM, Gene Wirchenko <[email protected]> wrote:
> At 03:23 2015-04-16, Laurie Alvey <[email protected]> wrote: > >> In my innocence, I wonder why you want to disallow NULLs? They are, IMHO, >> the best way to hold unknown or irrelevant column values. >> > > They get ambiguous. Take your example above. Does a null mean > unknown or irrelevant? The two are different cases. e.g. A employee's > salary might be unknown, or the employee might not be salaried. > > You can always record explicitly that something is unknown if you > want. > > Nulls poison expressions. The moment you have the possibility of a > null, you have to code handle nulls. Yes, the tables may be less complex, > but that complexity then has to be dealt with in the app code again and > again and again. > > Due to an error in SQL, summing a column in a table where there are > no matching rows gives a result of null. It should give a result of 0, > that being the identity element for addition. Because of this one glitch, > I have had to adjust results in several places in my system, replacing null > with 0. > > Sincerely, > > Gene Wirchenko > > [excessive quoting removed by server] _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: http://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/cajidmyjzxpi02z_bz+esa+gmpscaii3gbdezmi5uyyugps1...@mail.gmail.com ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
