Re: dumb terminology question: candidate key

Marshall Spight wrote:
> Does anyone have any insight or information on the origin
> of the term "candidate key"? It seems like a standout bad
> term in a field full of not-very-good terms.

i'd say the very word 'key' is an unfortunate one, although i can sympathize with Dr. Codd using it, given the context of the ignorant times thirty-five years ago. i've heard from various first-hand sources that not only was there resistance within IBM to his ideas but he was under constant attack, especially from IBM's powerful sales arm, so much so that some people thought his first stroke was due to it. perhaps he was using the term 'key' because in those days with the various file-systems, let alone IMS, it was a very common term. i have the impression that he wanted to use terminology that had some familiarity and wouldn't inflame the bigots.

as most people seem to use it today it is a subset of attribute values that are uni..ue (sorry, keyboard is broken, i mean no duplicates), in fact a constraint. i believe it is possible to avoid the term completely, since most relational algebras are capable of defining it without resorting to a 'keyword', although i don't know of any that are that rigourous.

>
> A "candidate" is something that aspires to a particular position,
> but hasn't attained it yet. So the term suggests that we're
> *considering* declaring this set of attributes to be unique,
> but we're not sure yet. We'll get back to you once we're sure.
> ...

following the political analogy, you might just as well call it a 'draft key'.

regarding terms, i remember reading that CJ Date said that 'normalization' had nothing to do with China. i don't have a copy anymore, but i also remember reading, i think it was in DBMS magazine around 1993, an interview with Edgar Codd where he said that he did in fact borrow the term around 1970 when Nixon was 'normalizing' 'relations' with that country. can anybody back up or refute this?

paul c. Received on Fri Jul 15 2005 - 22:38:53 CEST