Check the information_schema views. Particularly you want to look into
information_schema.key_column_usage and information_schema.table_contraints
The later gives you the constraint type (in your case 'PRIMARY KEY') and the
constraint name which you then can match to the constraint name in
key_column_usage to get all the columns that make up the primary key.
Hope that helps.
BTW: using the information schema is the bettwe way to go for system catalog
queries. Every major release will potentially have changes in the system
catalogs, where the views in the information schema won't change a lot.
They're designed to give you a stable API for the system catalogs.
On Tuesday 31 January 2006 08:48, Düster Horst wrote:
> I'm looking out for a system catalog query to select the primary key column
> name for a specific table. With the following query I only get the name of
> the primary key itself. How do I get the primary key column name???
>
> select pg_constraint.*,pg_index.indisprimary
> from pg_constraint,pg_namespace, pg_class, pg_index
> where pg_namespace.nspname='public'
> and pg_namespace.oid=c.connamespace
> and pg_class.relname='new_layer'
> and pg_class.oid=c.conrelid
> and pg_class.oid=pg_index.indrelid
> and c.contype='p'
>
> I'll appeciate any help.
>
> with best regards
>
> Dr. Horst Düster
>
> Kanton Solothurn
> Amt für Geoinformation
> Abteilung SO!GIS Koordination
> Rötistrasse 4
> CH-4501 Solothurn
>
> Tel.: ++41 (0)32 627 25 32
> Fax: ++41 (0)32 627 22 14
>
> horst.duester@bd.so.ch
> www.sogis.so.ch
>
>
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