On July 7, 2011 12:30:35 PM Rich Shepard wrote:
> On Thu, 7 Jul 2011, Alan Hodgson wrote:
> > It implies the composite is unique. Not sta_type.
>
> OK. Now I understand. How, then, do I add a unique constraint to each
> component of the composite key so I can add them as foreign keys to the
> station_information table? Or, is there another way to add those two
> columns to station_information and then add the foreign key constraints?
>
> Thanks for clarifying,
>
create unique index index_name on table (column).
Or I think you can create a foreign key on a composite like "foreign key
(column1,column2) references table (column1,column2)" which probably makes
more sense if that is a natural key.
