RE: Limits on referential integrity

John - Thanks for your insights. I appreciate you final comment that you haven't seen RI as the real performance problem. Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, January 22, 2002 7:40 AM
To: Multiple recipients of list ORACLE-L

Hi Dennis,

Just my opinion but I tried to follow these rules as a DBA.

1. If the business rule can be implemented with pk, fk, unique or check constraints I do it as such
2. If the business rule can be implemented as a trigger I code it as a trigger
3. If none of the above, I implement as a stored procedure and try to insure that every developer uses this procedure.

Occasionally I have heard the "performance discussion" in regards to constraints. In 5 years of consulting I have never had constraints be THE problem. But if I was a developer that had written some of the awful SQL I have seen, I might have tried [:-)] . Constraints do put a premium on error checking by the application on inserts/updates.

Hope this helps,
John

DWILLIAMS_at_LIFETOUCH.COM wrote:

>Jared - I wasn't clear, but then again it is Monday. I have a team of
>inexperienced developers starting a big, new Java application. They have a
>good, experienced data model consultant helping them create the data model.
>They are eager to include referential integrity. So eager it has me a
little
>worried. My question: "Is there too much of a good thing?". In Oracle 7,
>sometimes sites would remove RI to ensure good performance (we are starting
>this project on Oracle9i). Has anyone encountered problems with too many
>constraints? Any guidelines you use with developers? Thanks.
>Dennis Williams
>DBA
>Lifetouch, Inc.
>dwilliams_at_lifetouch.com
>
>
>-----Original Message-----
>Sent: Monday, January 21, 2002 4:16 PM
>To: Multiple recipients of list ORACLE-L
>
>
>I would be you lunch that what they are implementing in their
>code is not actually RI. They may be implementing code to
>ensure things get inserted in the right order, and that child rows
>have a parent.
>
>This is a very weak form of RI. Oracle is very good at implementing
>RI, and it is not dependent on an application. RI in the database
>is the route to choose unless there is some good reason not to.
>
>RI in the database will prevent orphaned data created through
>updates, deletes or even ( gasp! ) bugs in the app.
>
>Programmers tend to dislike RI in the database because it
>forces them to maintain data integrity in a transaction. This is
>not a bad thing, it just forces them to have a good understanding
>of their transactions.
>
>Point out to them that it is less code to write as well. :)
>
>Jared
>
>
>
>
>
>
>
>DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
>Sent by: root_at_fatcity.com
>01/21/02 01:35 PM
>Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> cc:
> Subject: Limits on referential integrity
>
>
>How much referential integrity should be implemented in Oracle? We are
>starting a large new Java project. Our current applications keep their
>referential integrity inside their own dictionary, so I haven't had to
>deal
>much with referential integrity recently. Can there be too much of a good
>thing? What guidelines do you tend to use? At this point the developers
>are
>designing the data model so they are busily linking all the little boxes.
>My
>attitude at this point is "implement what you've got and if there are
>performance problems we'll deal with them when they arise". Can anyone
>give
>me a better motto?
>Thanks.
>Dennis Williams
>DBA
>Lifetouch, Inc.
>dwilliams_at_lifetouch.com
>

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Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM

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