Re: Can we solve this -- NFNF and non-1NF at Loggerheads

strider5 wrote:

>>Maybe it's because I'm used to thinking relationally, but I just can't
>>think of any examples where a RVA would be necessary or even just
>> useful.

Why can't this be done in standard relations?

Surely you just have:

• one table (Tables?) with one row per tablename.
• another table (Keys?) with a primary key of {tablename, key_name} and maybe attributes to denote uniqueness etc.
• a third table (Key_Columns?) with a primary key of {tablename, key_name, col_name}

This is assuming you just want key names to be unique per table rather than database-wide, if not, remove the tablename column. Maybe I have some other details wrong, but you get the idea that it should be possible in principle.

Although this seems at first sight more complex because it uses more tables, I think it's better in the long run because it's forcing you to break down your knowledge into simple first-order predicates.

Paul. Received on Mon Feb 07 2005 - 11:08:33 CST