Add Update through Linq

Create one .dbml file and make DataBase connection there and drag and drop the table inside the Dbml window. and right clcik on the field which field u want primary key and select the property option and give there True as primary key.

protected void btnUpdate_Click(object sender, EventArgs e)
{
linqStudent linObj = new linqStudent();
var obj = linObj.Students.SingleOrDefault(o => o.Roll == txtRoll.Text);
if (obj != null)
{
obj.Name = txtName.Text;
linObj.SubmitChanges();
}
}

protected void btnAdd_Click(object sender, EventArgs e)
{
linqStudent linObj = new linqStudent();
Student objStdebt = new Student();
objStdebt.Name = txtName.Text;
objStdebt.Roll = txtRoll.Text;
linObj.Students.InsertOnSubmit(objStdebt);
linObj.SubmitChanges();
}