> I am in the impression that SQL join takes more time for > execution as well as space because database internally builds Cartesian > product and then evaluates for condition. No, that's a conceptual description, but the actual process is more optimized, often far more so if you have the appropriate indices. > Recently I normalized by DB > and changed my application Data model which resulted in writing lots of > inner join queries. Later I found that DB server is consuming more > memory. That can certainly happen. There is a tradeoff there, in that reduction of redundant data and the problems of maintaining it may require more CPU cycles and RAM to get data back out. > And once my Database also crashed. I am assuming that because of > normalization and inner joins, my DB crashed. Not likely. When you construct your joins, do be careful about the join conditions. A common mistake is to leave out a condition in the where clause which then results in the actual Cartesian product being requested. The more tables involved in a join, the easier it is to make such a mistake--I think we've all done this at one time or another. -- Scott Ribe scott_ribe@xxxxxxxxxxxxxxx http://www.killerbytes.com/ (303) 722-0567 voice
