I'm trying to design a content management database (logical design only), but I'm stuck.

The database must store multimedia, and the documents must be searchable, so I have a content table.

Since some of the data will be blob, and some clob - I don't want to store it all in the same table for normalisation reasons, but if I have seperate tables for blob and clob data.. how can I link them back? I'm stuck with the same problem of one field being empty..

I think I'm missing something fundamental..

Any help greatly appreciated.