From 470a1048ec145fe16b5baea56b9aef93f9878747 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 1 Sep 2002 16:28:06 +0000
Subject: plpgsql functions can return RECORD, per Neil Conway.

---
 doc/src/sgml/plpgsql.sgml |  4 +---
 doc/src/sgml/xfunc.sgml   | 23 ++++++++++++++++++++++-
 2 files changed, 23 insertions(+), 4 deletions(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 4da3f3c0405..998ed72089e 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/plpgsql.sgml,v 1.5 2002/08/30 00:28:40 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/plpgsql.sgml,v 1.6 2002/09/01 16:28:05 tgl Exp $
 -->
 
 <chapter id="plpgsql"> 
@@ -538,8 +538,6 @@ END;
 
    <para>
     Note that <literal>RECORD</> is not a true data type, only a placeholder.
-    Thus, for example, one cannot declare a function returning
-    <literal>RECORD</>.
    </para>
   </sect2>
 
diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index 9a7b79f0ddd..3999bf81769 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.59 2002/08/30 00:28:40 tgl Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.60 2002/09/01 16:28:05 tgl Exp $
 -->
 
  <chapter id="xfunc">
@@ -2119,6 +2119,27 @@ SELECT * FROM vw_getfoo;
 </programlisting>
     are all valid statements.
    </para>
+
+   <para>
+    In some cases it is useful to define table functions that can return
+    different column sets depending on how they are invoked.  To support this,
+    the table function can be declared as returning the pseudo-type
+    <type>record</>.  When such a function is used in a query, the expected
+    row structure must be specified in the query itself, so that the system
+    can know how to parse and plan the query.  Consider this example:
+<programlisting>
+SELECT *
+FROM dblink('dbname=template1', 'select proname, prosrc from pg_proc')
+  AS t1(proname name, prosrc text)
+WHERE proname LIKE 'bytea%';
+</programlisting>
+    The <literal>dblink</> function executes a remote query (see
+    <literal>contrib/dblink</>).  It is declared to return <type>record</>
+    since it might be used for any kind of query.  The actual column set
+    must be specified in the calling query so that the parser knows, for
+    example, what <literal>*</> should expand to.
+   </para>
+
   </sect1>
 
   <sect1 id="xfunc-plhandler">
-- 
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