Franz.Rasper@izb.de wrote:
>
> > Make the table:
>
> > id | year | value
> > ---+------+------
> > 1 | 1970 | 23
> > 1 | 1971 | 25
> > 1 | 1972 | 28
> > ...
> > 2 | 1972 | 5
> > 3 | 1971 | 94
> > 3 | 1972 | 102
>
> > primary key: (id,year)
> > value not null
> > and be ready.
> >the import/update reasons are pretty easily solved
> >that way too.
>
> then your primary key will consists of two fields.
> I prefer the primary keys with one field only.
Is there any reason for that preference?
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
