Re: [GENERAL] PL/pgsql return resultset/cursor?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Richard Emberson <emberson(at)phc(dot)net>
Cc: PostgreSQL-documentation <pgsql-docs(at)postgresql(dot)org>
Subject: Re: [GENERAL] PL/pgsql return resultset/cursor?
Date: 2002-04-09 03:34:15
Message-ID: 200204090334.g393YFE14191@candle.pha.pa.us
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I have added an FAQ item and improved the documentation. Seems the
official current docs aren't being built regularly, (last April 3), so I
pointed to my web copy in the FAQ:

4.25) How do I return multiple rows or columns from a function?

You can return result sets from PL/pgSQL functions using refcursors. See
http://candle.pha.pa.us/main/writings/pgsql/sgml/plpgsql-cursors.html,
section 23.7.3.3.

---------------------------------------------------------------------------

Richard Emberson wrote:
> Thanks for the example. Whoever maintains the documentation ought to put such
> an
> example in the refcursor section.
>
> Richard
>
>
> Bruce Momjian wrote:
>
> > Jan Wieck wrote:
> > > Richard Emberson wrote:
> > > >
> > > > Is it possible to return a result-set or cursor from a PL/pgsql
> > > > procedure, like
> > > >
> > > > CREATE OR REPLACE FUNCTION foo()
> > > > RETURNS <WHAT_TYPE> AS '
> > > > BEGIN
> > > > RETURN SELECT * from FOO;
> > > > END;
> > > > ' LANGUAGE 'plpgsql';
> > > >
> > > > If you open a cursor in a procedure, it gets closed when the procedure
> > > > exits, right?
> > >
> > > Cursors get closed in PostgreSQL when you close them or when
> > > the transaction ends.
> > >
> > > Look at the refcursor data type (new in v7.2) and use
> > > transactions.
> >
> > Here is a sample:
> >
> > create table aa(a int, b int, c int);
> > create function f() returns refcursor as '
> > declare
> > r refcursor;
> > begin
> > open r for select * from aa;
> > return r;
> > end;' language 'plpgsql';
> >
> > --
> > Bruce Momjian | http://candle.pha.pa.us
> > pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
> > + If your life is a hard drive, | 830 Blythe Avenue
> > + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 1: subscribe and unsubscribe commands go to majordomo(at)postgresql(dot)org
>
>

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026

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