Re: unique across two tables

On Mon, 20 Jun 2011 19:42:20 +0200
Alban Hertroys <dalroi(at)solfertje(dot)student(dot)utwente(dot)nl> wrote:

>On 20 Jun 2011, at 17:03, Tarlika Elisabeth Schmitz wrote:
>
>> I have two tables, town and townalias, the latter containing
>> alternative town names.
>> I would like to ensure that a town name is unique per
>> country-region across the two tables.
>>
>> Can I do this with a constraint ot do I need to implement the logic
>> via trigger?
>
>
>This is very similar to what was recently discussed in the topic
>"Constraint to ensure value does NOT exist in another table?" in this
>list.

Thanks - found it:
http://postgresql.1045698.n5.nabble.com/Constraint-to-ensure-value-does-NOT-exist-in-another-table-td4493651.html

--

Best Regards,
Tarlika Elisabeth Schmitz