Quoting Steve Adams <steve.adams@xxxxxxxxxxxx>: > You are right. > If it is a logical data model, then fight for 3NF, if not BCNF. > But in physical database designs, denormalization should be normative > if it will improve application efficiency and > if it will not hinder development and maintenance. > Just my opinion, of course. > > -----Original Message----- > From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On > Behalf Of Chris Stephens > > There is a discussion going on at work concerning calculated fields. > > I am claiming that any calculated field in a table is a violation of > at least 3NF if not 2NF. I can find all sorts of references on the > web that justify my position but nothing that directly says this > violates normalization rules. > > The person who i disagree with is claiming that 'technically', > calculated fields do not violate 3NF. They are just not recommended. > I am unable to find anything on the web coinciding with this argument. > > Anyone know of a site with a direct statement that calcualted fields > violate 2NF/3NF? As far as I can recall calculated fields violate 3rd normal form as they are transitive values. However, like Steve said: if it helps speed up access with physical design, then it is probably fine to use them. I'd look at using MVs for that sort of functionality, though. -- Cheers Nuno Souto from sunny Sydney -- //www.freelists.org/webpage/oracle-l