how to update data in database using Linq in asp,net

Try this:
Follow the steps:
1. Create the object of your DataContext.
2. Get the row of the table which you want to update.
3. Update the values in the required columns.

//context is the object of your datacontext
var dbEmpInfo = context.Employee
    .Where(w => w.EmployeeID == 101)
    .SingleOrDefault();

if (dbEmpInfo != null)
{
    dbEmpInfo.FirstName = "Amit";
    db.SubmitChanges();
}

You should try searching Google[^] also.

--Amit