m_conn.rollback();
if (commit) { m_conn.commit(); } else { m_conn.rollback(); }
    private void teardown() throws SQLException {        Statement stmt = m_conn.createStatement();        try {            for (Iterator it = m_constraints.iterator(); it.hasNext(); ) {                Constraint con = (Constraint) it.next();                stmt.execute("alter table " + con.getTable().getName() +                             " drop constraint " + con.getName());            }            Collection tables = m_root.getTables();            for (Iterator it = tables.iterator(); it.hasNext(); ) {                Table table = (Table) it.next();                stmt.execute("drop table " + table.getName());            }        } finally {            stmt.close();            m_conn.rollback();            m_conn.close();            m_constraints = null;            m_conn = null;            m_root = null;        }    }