Re: Database design, Keys and some other things
Date: Wed, 28 Sep 2005 16:57:33 +0300
Message-ID: <dhe7gh$ds5$1_at_domitilla.aioe.org>
"-CELKO-" <jcelko212_at_earthlink.net> wrote in message
news:1127914182.462827.172910_at_g47g2000cwa.googlegroups.com...
> 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.
I understood that the VALUE of the SURROGATE cannot be seen and controlled, not the SURROGATE. Are the VALUE and the SURROGATE the same thing ? Received on Wed Sep 28 2005 - 15:57:33 CEST