虽然我会美元给人一种角色ID列都tables.Here p $ @ PFER小罗的是，您可以在不干扰数据库做什么。

Although i would prefer @ronaldinho's way of giving a RoleId column to both tables.Here is what you can do without disturbing the database.

刚上登录page.So添加的项目老师和学生一个DropDownList当有人试图登录，他们必须选择自己的角色，然后输入。这样你就可以直接code作为

Just add a dropdownlist with items "Teacher" and "Student" on your login page.So when some one tries to log in they have to select their role and then enter. This way you can direct the code as

   protected void Button1_Click(object sender, EventArgs e)
    {
        if (dropdownrole.SelectedItem.Text == "Admin")
        {
            Admin();
        }
        else if (dropdownrole.SelectedItem.Text == "Student")
        {
            Student();
        }
        else if (dropdownrole.SelectedItem.Text == "Teacher")
        {
            Teacher();
        }
    }

看看它有可能为你

See if it is possible for you