Foreign key pointing to multiple tables

I have found a problem that I can't seem to solve in what I consider a nice way.

Basicly I have a table called Jobs. Each Job has some details in its table, it also has a type. These are A, B, C, D, E and F. If it is of type A then it needs an additional 10 columns, B 13, C 30 and so on. These additional piecies of information are totally unrelated to those in a different letter. How do I represent this?

My first thought was to have a Jobs table which has a foreign key pointing to a Type table, which lists the types, and then a column which has a foreign key to either Table A, Table B, Table C etc. This would them mean that there was a foreign key that pointed to different tables depending on what another column's data said.

Is that even slightly valid relational database thinking? If not what is a better solution? All I could really think of was having an A_key column, a B_key column etc, but then there would be loads of null data.

Cheers,

Chris Received on Wed Sep 17 2003 - 15:35:16 CEST