        modifying the database (that is, performing
                        <code class="literal">INSERT</code>, <code class="literal">UPDATE</code>,
                        or <code class="literal">DELETE</code>). RESERVED locks and read
                        locks can co-exist.
                    </p>
            </li>
            <li>
              <p>
                        <code class="literal">BEGIN EXCLUSIVE</code>
                    </p>
              <p>
                        Begins the tran