Re: Does Codd's view of a relational database differ from that ofDate& Darwin? [M.Gittens]
Date: Mon, 06 Jun 2005 15:38:31 GMT
Message-ID: <X5_oe.1587048$8l.519586_at_pd7tw1no>
Alexandr Savinov wrote:
>
> ... If something disappears, if something is
> deleted then acutally we get null.
i think we get 'false', according to the CWA.
> ...
i'd like to know what problem the never-ending arguments about nulls are aimed at. in mundane applications at least (which i think is where most people spend their time), what is the problem with using empty strings for unknown names or zeroes for unknown number values? if the db user has allowed tuples with such attribute values then they should expect to have to judge the results accordingly, such as ones produced by aggregate functions. if they want to record some other kind of 'meta-data' such as keying problems, then they can define relations specific to those.
pc Received on Mon Jun 06 2005 - 17:38:31 CEST