INSERT INTO db(a,b) VALUES (key, data);

RETURN;

EXCEPTION WHEN unique_violation THEN

--do nothing, and loop to try the UPDATE again

--Do nothing, and loop to try the UPDATE again.

END;

END LOOP;

END;

SELECT merge_db(1, 'david');

SELECT merge_db(1, 'dennis');

</programlisting>

This example assumes the <literal>unique_violation</> error is caused by

the <command>INSERT</>, and not by an <command>INSERT</> trigger function

on the table. Also, this example only works in the default Read

Committed transaction mode.

</para>

</example>

</sect2>