protected void add() {
		if (!dialog.showAddDialog())
			return;// ûȡζԻ

		// ݿв,ɹѧstudents
		if (database.addStudent(dialog.student)) {
			students.add(dialog.student);
			this.updateDisplay();
		} else
			JOptionPane.showMessageDialog(this, "ӵѧѧѧѧųͻ",
					"ѧʧ", JOptionPane.WARNING_MESSAGE);
	}