Re: Indexes and Foreign Keys

"Mladen Gogala" <gogala_at_sbcglobal.net> wrote in message news:pan.2006.03.12.05.59.50.918028_at_sbcglobal.net...
> On Sat, 11 Mar 2006 20:09:37 -0700, Mark A wrote:
> I really don't do polls among DBA people. I've met my betters several
> times. I've met Tim Gorman, Jonathan Lewis, Tanel Poder, Arup Nanda and
> Paul Drake. I have never met Tom Kyte, Cary Millsap, Dan Fink, Steve
> Adams, Howard Rogers, Richard Foote, James Morle, Gaja Vaidayanatha, K.
> Gopalakrishnan and Connor McDonald, all of whom I consider much more
> knowledgeable then myself. Judging about the "average DBA" would be
> nothing short of preposterous arrogance on my part. Furthermore, I
> firmly believe that no such creature as an "average DBA" exists in
> the wild. Frequently, technical knowledge isn't even the most
> important characteristic of a DBA. Good personality, good working
> relationship with your coworkers and the ability to carry out the
> orders of the management are equally as important as a good technical
> knowledge. The letter "A" in the abbreviation DBA stands for
> "Administrator". DB administrator is an administrator, a part of a
> bureaucracy, which means that he must understand his place in the pyramid
> and fit in. Most of the commercial environments are not MIT, Lawrence
> Livermore or Chase Manhattan. Most of the commercial environments are
> doing business happily with DBA personnel far less knowledgeable then Cary
> Millsap, Tom Kyte or Steve Adams. The most important secret of a good DBA
> is the attitude: he mustn't see the DBA position as a position of a guru,
> artist or a rock-star, he must learn a thing or two about the company
> business, know enough to make a valuable contribution to the company
> business and know when to call in the calvary, the big guys from renowned
> consulting companies like Hotsos, TUSC, JL Computer Consultancy or Ixora.
> To quote the "Life of Brian", we're all individuals. There is no such
> creature as an average DBA on the face of the planet. An average
> developer, however, is a different matter altogether.
>

I didn't say anything about the "average DBA." Nowhere did I use the term "average DBA." I just said that only a small number of DBA's understand which FK's don't need indexes. That is why many experts just recommend that every FK have an index, precisely because they have learned from experience that the vast majority of DBA's can't figure it out for themselves, and it is generally considered better to have to many indexes than to risk a situation where a needed index is not created.

Many DBA's are very good technically, but they have no idea about how the application is used, what the data is, or other important things that one would need to know to decide when an index on foreign key is not necessary.

True, many applications are packages, or the DBA inherited the system that was developed by someone else, and under those circumstances it is more difficult to understand these issues. So it is not "always" their fault that they don't have enough information to make these decisions correctly.

Moreover, very few DBA's have a good business background that would enable them to understand a particular application, even if they did not have any knowledge of the specific application and database implementation they are supporting. For example, a DBA who had an accounting background and had worked with other Accounts Payable systems would have a pretty good idea of how any implementation of Accounts Payable would work, and would be better able to make decisions about when indexes are needed. Received on Sun Mar 12 2006 - 00:49:58 CST