anonymous wrote : This isn't a relational issue. Right, because in this kind of usage your Entity design simply lacks. This solution is a workaround. In most cases one is not able to tidy up, normalize an already implemented ER model. The one and only solution is to have a 3rd NF ER model - most times impractical. Here comes the DB views for select statements on _denormalized_entities_ (ER entities, not EJB ;) in the mind. In the case of your NULL columns, your ER model is not even in the 1st NF. NULL means 'column does not exist here'. NULL is is a 'workaround' in RDBMSes for not to force to normalize till the 5th NF everywhere. Ok, 3rd NF ;)
anonymous wrote : Huh?!? More than half a table's columns are often optional. Reading may be of help: I wrote '_significant_ '. anonymous wrote : Any column can be filtered via a parameterized where clause in the real world. I know, but you are not working in a real world, you are talking about a RDBMS. Exactly the fields in a where clause are kind of keys, if you are happy with this or not. Even in a single table query. anonymous wrote : How is having multiple optional columns a bad model? | See above regarding _significant_. This is not what I am trying to explain: Building relations, (if clauses like where statements) even between the same table based on unnormalized data is not possible. Real world: ... in most cases. What i suggest is to normalize your model for your queries via DB views and than use EJB. Dont blame the J2EE for not resolving bad RDBMS design _and_usage_. Buy a book about ER modelling and implementing this model in RDBMS and a pump gun for the DB designer (most often the noise is sufficient). bax View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=3836395#3836395 Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&p=3836395 ------------------------------------------------------- This SF.Net email is sponsored by: Oracle 10g Get certified on the hottest thing ever to hit the market... Oracle 10g. Take an Oracle 10g class now, and we'll give you the exam FREE. http://ads.osdn.com/?ad_id=3149&alloc_id=8166&op=click _______________________________________________ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
