Re: Database design, Keys and some other things

-CELKO- wrote: 
Dr. Codd: "..Database users may cause the system to generate or delete
a surrogate, but they have no control over its value, nor is its value
ever displayed to them ..."(Dr. Codd in ACM TODS, pp 409-410) and Codd,
E. (1979), Extending the database relational model to capture more
meaning.  ACM Transactions on Database Systems, 4(4).  pp. 397-434.

This means that a surrogate ought to act like an index; created by the
user, managed by the system and NEVER seen by a user.  That means never
used in queries, DRI or anything else that a user does.
...

thanks, i'd never paid much attention to the idea before. seems like a bizarre one, if i may say so. i can just imagine trying to explain it to a properly nosy user, eg.: "well the database did it that way because of the surrogate key ... what? ... how do i know there aren't two of them? ... well, i just *know* ... what? ... no, you can't see it!"

if one agrees that there are more basic problems to be solved, it doesn't seem like a very important idea, but if a guy as smart as Codd put it forth, i guess i should try harder to understand it.

p

.

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