On Fri, 2003-01-24 at 10:54, Prokopis Prokopidis wrote:
> Yes, but "3 tables" was just an example. What if I have 10 or 1000
> tables that need a comment? This CHECK solution becomes "ugly" very
> quickly. There must be another way ...
In that case, create a new table fkeys, for example:
create table fkeys (
id text primary key,
table TEXT NOT NULL
};
Then each id in students, teachers, etc. has a foreign key reference to
fkeys and each comment similarly has a foreign key on fkeys.
You would need to add your own triggers to drop items from fkeys when
they are deleted from the other tables.
The ideal would be to use inheritance and have a direct fk reference
from comments to the parent table, but that won't work at the moment.
--
Oliver Elphick Oliver.Elphick@lfix.co.uk
Isle of Wight, UK http://www.lfix.co.uk/oliver
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