Re: Traversing large data table

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From: Joe Celko (jcelko212_at_earthlink.net)
Date: 11/02/04 

Date: Tue, 02 Nov 2004 14:12:05 -0800

a quote from 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.

Sounds pretty clear to me. What part of "no control over" and "nor ever
displayed" did I miss?

To me 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. For example,
Sybase SQL Anywhere does a nice job of building pointer chains to
co-ordinate PK-FK relationships and cascade their DRI actions, but you
do not get to do pointer arithmetic, re-seed them or anything else like
you do in T-SQL.

--CELKO--
Please post DDL, so that people do not have to guess what the keys,
constraints, Declarative Referential Integrity, datatypes, etc. in your
schema are. Sample data is also a good idea, along with clear
specifications.

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