tfield">is_null_call</code> <code class="type">yes_or_no</code>
      </p>
      <p>
       If the function automatically returns null if any of its
       arguments are null, then <code class="literal">YES</code>, else
       <code class="literal">NO</code>.  Null for a procedure.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">sql_path</code> <code class="type">character_data</code>
      </p>
      <p>
       Applies to a feature not 