On Mon, 20 May 2002, Thirumoorthy Bhuvneswari wrote:
> hi,
> I am using Postgresql-7.1.3 with Redhat Linux-7.1 for
> my application developed in Java. I have created some
> tables with foreign keys which are not the primary
> keys in the master tables. Its working fine in
> Linux-7.1.3. I tried to upgrade my system with
> Postgresql-7.2 and did restore of my database. It did
> not accept such foreign keys. Though the design may
> not be of its best normalization form, I use such
> foreign keys for ease of maintenance. How can I get
> them in Postgresql-7.2. Thanks in advance.
Well, the values do not necessarily need to be primary keys,
but they must be unique. Even in 7.1.x, there was no
check done to guarantee that the values are unique,
but for non-unique referenced columns the results
would sometimes end up being incorrect.