rm_upsert.patch

Index: doc/src/sgml/plpgsql.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/plpgsql.sgml,v
retrieving revision 1.156
diff -c -6 -r1.156 plpgsql.sgml
*** doc/src/sgml/plpgsql.sgml	29 Jul 2010 19:34:40 -0000	1.156
--- doc/src/sgml/plpgsql.sgml	5 Aug 2010 17:34:54 -0000
***************
*** 2332,2382 ****
       linkend="errcodes-table"> for a list of possible error
       codes). The <varname>SQLERRM</varname> variable contains the
       error message associated with the exception. These variables are
       undefined outside exception handlers.
      </para>
  
-     <example id="plpgsql-upsert-example">
-     <title>Exceptions with <command>UPDATE</>/<command>INSERT</></title>
-     <para>
- 
-     This example uses exception handling to perform either
-     <command>UPDATE</> or <command>INSERT</>, as appropriate:
- 
- <programlisting>
- CREATE TABLE db (a INT PRIMARY KEY, b TEXT);
- 
- CREATE FUNCTION merge_db(key INT, data TEXT) RETURNS VOID AS
- $$
- BEGIN
-     LOOP
-         -- first try to update the key
-         UPDATE db SET b = data WHERE a = key;
-         IF found THEN
-             RETURN;
-         END IF;
-         -- not there, so try to insert the key
-         -- if someone else inserts the same key concurrently,
-         -- we could get a unique-key failure
-         BEGIN
-             INSERT INTO db(a,b) VALUES (key, data);
-             RETURN;
-         EXCEPTION WHEN unique_violation THEN
-             -- do nothing, and loop to try the UPDATE again
-         END;
-     END LOOP;
- END;
- $$
- LANGUAGE plpgsql;
- 
- SELECT merge_db(1, 'david');
- SELECT merge_db(1, 'dennis');
- </programlisting>
- 
-     </para>
-     </example>
    </sect2>
    </sect1>
  
    <sect1 id="plpgsql-cursors">
     <title>Cursors</title>
  
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