public boolean Exist(String Tea_ID, String PassCode) {
        try {
            StringBuffer sql = new StringBuffer();
            sql.append(" select * from teacher where");
            sql.append(" tea_ID='");
            sql.append(Tea_ID);
            sql.append("' && teacher_Passcode='");
            sql.append(PassCode);
            sql.append("';");

            SQLHelper sqlHelper = new SQLHelper();
            sqlHelper.sqlConnect();
            ResultSet rs = sqlHelper.runQuery(sql.toString());
            if (rs.next()) {
                return true;
            }
        } catch (SQLException ex) {
            Logger.getLogger(Student_DAO.class.getName()).log(Level.SEVERE, null, ex);
            return false;
        }
        return false;

    }