"Richard Heyes" <richardh@xxxxxxxxxxx> wrote in message news:481EF634.6010705@xxxxxxxxxxxxxx >> I do not agree that creating a database which is normalised to3NF is a >> waste of time. > > It isn't always, but it is sometimes. When time is a (significant) factor, > getting something up and running (which has acceptable performance) may be > more impotant than creating a technically perfect solution. In fact > creating something that is technically perfect is often just a pipe dream > for programmers. You obviously do not understand what "technically perfect" means when it comes to data normalisation. 3NF is considered to be "good enough" while 4NF, 5NF and 6NF is considered to be "perfect". But there is such a thing as "too perfect" which is why even C J Date (the father of relational theory) said that de-normalsation is an acceptable practice. Every database designer worth his salt should be able to achieve 3NF without breaking into a sweat, while 4/5/6NF are entirely optional, and only worth it under paricular circumstances. > > On the contrary, a totally un-normalised database is nothing but a >> problem waiting to bite you in the a**e. > > So you can: > > a) Create something that gets you to market as fast as possible that is > "good enough". > b) Optimise/adjust the structure later. > > IME though, b) rarely happens. That's why solutions which are thrown together are often incapable of being expanded to include new requirements. If you create a "throw away" solution then never try to expand it, simply throw it away and start again. -- Tony Marston http://www.tonymarston.net http://www.radicore.org > > Computer systems have a habit of >> growing over time > > Really? > >> ...and if you don't follow the rules of normalisation your database will >> end up as the biggest bottleneck. > > Granted it's more likely, but not a given. You just need developers who > have discipline, oh and a good memory helps. > >> Anyone who doesn't know how to reach 3NF shouldn't be designing >> databases. > > Rubbish. It helps, in particular for how you can optimise you structure > without duplicating data (too much), but shouldn't be a requirement. > > -- > Richard Heyes > > +----------------------------------------+ > | Access SSH with a Windows mapped drive | > | http://www.phpguru.org/sftpdrive | > +----------------------------------------+ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
