Re: Help: creating view with different columns?

Juergen Weber wrote: > > There is a database of quite different articles. The customer > wants us to put everything into one single table. > All articles have the article number column in common, but > mostly columns are only used for some articles. So the resulting > matrix is very sparsely populated. > This is a classical design problem with relational databases. The fact that the customer wants to half-design it for you is a much more difficult problem and not one I can solve for you ;-) There are typically three options: a) one table with lots of NULL values b) one table with one row per attribute value c) one table for each subtype In an object-relational database such as Illustra or ODB-II you would naturally model it as one "super-table" with lots of "sub-tables", so the data would be physically stored as one table for each sub-type, but you could view it as one table for the super-type. I think, from the form of your question about views, this is the solution you are looking towards. Other people have suggested (b), and I have often had to resort to such designs myself, but it does make query very awkward and very inefficient. Mike Kay M.H.Kay@iclnet.co.uk