tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">is_deterministic</code> <code class="type">yes_or_no</code>
      </p>
      <p>
       If the function is declared immutable (called deterministic in
       the SQL standard), then <code class="literal">YES</code>, else
       <code class="literal">NO</code>.  (You cannot query the other volatility
       levels available in <span class="productname">PostgreSQL</span> through the information schema.)
     