Linq to entity delete a specific column from a table - asp.net

Question

Linq to entity query to delete a specific column from a table by matching a condition`
public ActionResult deleteChecks(string checkValue)
{
check_master checks = (from table in db.check_master
where table.check_code == checkValue
select table).First();
//now how to delete/remove checks.mcheck
return View("Edit");
}`
Only want to update a single column element with null value(of selected row) from the table check_master

Answer 1

You can set a single property (which maps to a column) to null and save it to the database
foreach(check_master check in checks)
{
check.mcheck = null;
}
db.SaveChanges();

Answer 2

using (NorthwindDataContext db = new NorthwindDataContext())
{
// Retrieve the existing entity. Database Call 1
Product product = db.Products.First(p => p.ProductID == 1);
// Change the properties. LINQ to SQL knows
// these specific properties have changed.
product.UnitsInStock = 14;
// Flush the changes. Database Call 2
db.SubmitChanges();
}

Answer 3

Entity framework works with constant table scheme only.
Tell please, what your global aim is, may be there's some more suitable way to do it.
Updated:
foreach(var chm in db.check_master)
{
chm.mcheck = null;
}
db.SaveChanges();

Answer 4

I believe that Linq to Entities only support DML, it does not support DDL operations.
So you would have to use stored procedure or ADO.NET raw query.
EDIT
you can do simple update like this :
public ActionResult deleteChecks(string checkValue)
{
check_master checks = (from table in db.check_master
where table.check_code == checkValue
select table).First();
checks.mcheck = null;
db.SaveChanges();
return View("Edit");
}`