code: public void clean() throws DBCleanException
     {
        try
        {
           execute(cleaningScripts);
        }
        catch (SQLException e)
        {
           throw new DBCleanException(JDBCUtils.getFullMessage(e), e);
        }
     }
docs: Clean JCR tables, can't contain some indexes or constraints,
  should be added on {@link #commit}. It done for possibility to restore
  data without any violations.
  
  <br>
  This method does not invoke commit or rollback on {@link Connection} but
  needed autocommit mode can be set.
  
  @throws DBCleanException