Stuart McLachlan
stuart at lexacorp.com.pg
Tue Jun 15 18:27:50 CDT 2004
On 15 Jun 2004 at 10:18, Francis Harvey wrote: > > You also have an inordinate amount of faith that people aren't using > the surrogate key except in the database. I don't know about you, but > I have no doubt that my database generated movie rental id, library > card id, etc. are not being shadowed by an internal surrogate key. > They have actually given me a card with the key on it, and it > definitely isn't formed by collapsing other attributes to form an > artificial key. It happens. > If those systems are using an internally derived Primary Key and using that same value as your assigned library card ID or movie rental ID they are poorly designed for all the reasons that have been discussed ad nauseum over the last several iterations of this debate. A common way to generate these sorts of "membership ID"s is to use the next *currently available* number. There is no guarantee that your club memebrship, library card etc ID was not used previously for another member. -- Lexacorp Ltd http://www.lexacorp.com.pg Information Technology Consultancy, Software Development,System Support.