Re: Discuss Data Design
Date: Sat, 21 Jan 1995 18:29:23 GMT
Message-ID: <D2rq0z.J9E_at_eskimo.com>
Keep in mind that the person doing the following post might not have encountered every possible variations of databse designs. It is just purely theoretical arguments !
I personally have experienced a tremendous improvements in correctly de-normalized tables. In fact, the query speed changed from 15 minutes to 10 seconds !!! This is due to the fact that I did not have to join 3 huge tables twice (plus a few other tables) in order to get the data I need ! (Yep, each of that 3 huge tables and some of those other tables had to appear TWICE.) Embedded "select" didn't help either (in rare instances, embedded "select" may speed up a query. I have also experienced this in the real world)!
By the way, to save you time, don't bother e-mail me about using indexes, arranging the tables correctly in the "from" clause and enabling, disabling indexes in the "where" clause and all those crap. I know them so well that I can do them in my sleep. I have also done tons of optimizations myself (too many, if you ask me. If you don't, too bad for you <grin>) and I know how to use "tkprof" and "explain" (for obvious reasons).
I am not good. I just have good mentors.
Mr. Kim Ng (President)
Paradigm Computer Consulting, Inc.
20611 E. Bothell Everett Hwy. S.E., Suite 280
Bothell, WA 98012
e-mail: kimmng_at_eskimo.com
Steve Edelstein (74160.645_at_CompuServe.COM) wrote:
: Don't de-normalize to cut down on join loads. It makes the
: database hard to maintain/enhance. Joins are optimized by using
: indexes correctly. There should never be a problem with joins if
: they're done correctly! In fact, there's really NEVER a reason to
: de-normalize. It makes your life harder in the long term (altho
: it may seem easier short term). The idea of normalized data is
: central to relational databases. It separates them from the
: hierarchical ones, and means you can use the db and its tools as
: they were intended.
: I think its better to have one large table (with views for each
: year, for instance). This is also a matter of maintenance ease as
: well as processing efficiency. This may ba a personal preference,
: and there may be arguments about it (but NOT about
: normalization!).
: --
: Steve Edelstein VOICE: 212-956-3670
: Relational Business Systems CompuServe: 74160,645
: 124 West 60th Street Suite 47C Author of
: New York, NY 10023 "Learning Oracle Forms"
Received on Sat Jan 21 1995 - 19:29:23 CET