-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 02/01/07 22:19, Paul E Condon wrote: > The recent heated discussion as to the relative merits of MySQL and > PostgresSQL reminded me of a question that I want to ask of RDBMS > experts, particularly experts who are willing to take a clear > position. Namely, what do you think of the work of C. J. Date? He > rejects SQL, as far as I can tell. Is there any support for this > position in the real world? Or in the academic world? What of > his objection to null 'values'? How does this play out when doing > mission critical DB? Does it matter? Or are there standards > techniques for avoiding any need for nulls? > > I look forward to reading an interesting discussion.
"SQL" isn't a complete/correct "expression" of relational algebra. So, it can't express the full power of Codd/Date's theories. As to support for this position in the real world, there's not much, if any; SQL is Good Enough For Most Uses. As for nulls, I don't see a problem with them. In fact, I think you need them, in order to describe "unknown" data. Non-DBMS systems make you use a "special value", but if any bit of data actually has that "special value", you're hosed. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFFwtliS9HxQb37XmcRApU4AKDbLEZLPw7Q3RJGqn3tykMRNv5n4gCgpvBR XBFBpSlYyngL9YT1Q6hp1RY= =lewk -----END PGP SIGNATURE----- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
