Re: Returning the name of a primary key

Tom, Juan,

Wouldn't this simple SQL do the trick?

CREATE OR REPLACE FUNCTION pk_column(text) RETURNS SETOF text
AS '
SELECT attname::text
FROM pg_class, pg_constraint, pg_attribute
WHERE pg_class.oid = conrelid
AND contype=''p''
AND attrelid = pg_class.oid
AND attnum = ANY (conkey)
AND relname=$1;
'
LANGUAGE sql VOLATILE STRICT;

> -----Original Message-----
> From: pgsql-hackers-owner(at)postgresql(dot)org
> [mailto:pgsql-hackers-owner(at)postgresql(dot)org] On Behalf Of Tom Lane
> Sent: Tuesday, May 17, 2005 4:49 AM
> To: Juan Pablo Espino
> Cc: pgsql-hackers(at)postgresql(dot)org
> Subject: Re: [HACKERS] Returning the name of a primary key
>
> Juan Pablo Espino <jp(dot)espino(at)gmail(dot)com> writes:
> > I need to write a function that retrieve the name of at least one
> > table primary key, if it exists. The only argument passed to the
> > function is the table name. I have thought something like this:
>
> You need to be searching the list of indexes, not the
> attributes per se.
> ATExecDropNotNull() might be a useful example.
>
> regards, tom lane
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index
> scan if your
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>
>