更新语句

String sql = "update student set num=?,name=?,birthday=?,score=?,password=? where id=?";

ps = conn.prepareStatement(sql);

ps.setString(1, student.getNum());

ps.setString(2, student.getName());

ps.setString(3, student.getBirthday2());

ps.setDouble(4, student.getScore());

ps.setString(5, student.getPassword());

ps.setInt(6, id);

删除

String sql="delete from student where id=?";

ps=conn.prepareStatement(sql);

ps.setInt(1, id);

ps.executeUpdate();

插入

String sql = "insert into student(num,name,birthday,score,password) values(?,?,?,?,?)";

ps = conn.prepareStatement(sql);

ps.setString(1, student.getNum());

ps.setString(2, student.getName());

ps.setDouble(4, student.getScore());

ps.setString(5, student.getPassword());

ps.setString(3, student.getBirthday2());

查询

String sql = "select * from student where num=? and password=?";

// 获取DB操作对象

ps = conn.prepareStatement(sql);

// 为动态参数赋值

ps.setString(1, num);

ps.setString(2, password);