On July 7, 2011 11:55:25 AM Rich Shepard wrote:
> On Thu, 7 Jul 2011, Alan Hodgson wrote:
> > You need a unique index on station_type.sta_type
>
> Alan,
>
> station_type(sta_type) is part of a composite primary key. Doesn't
> primary key automatically imply unique and not null?
It implies the composite is unique. Not sta_type.