c# - Update records using LINQ

Question

I need to set a value in a table for a subset of rows. In SQL, I would do this:

UPDATE dbo.Person SET is_default = 0 WHERE person_id = 5

Is there a way to do this in LINQ?

I currently use the:

var result = (from p in Context.People....)

notation.

Is there an update method I can use? Or do I have to get all the records, then update them one-by-one in a Foreach?

Is this the most efficient way, if this is even possible?

(from p in Context.person_account_portfolio where p.person_id == personId select p)
   .ToList()
   .ForEach(
       x =>
       x.is_default =
       false);

Answer 1

I assume person_id is the primary key of Person table, so here's how you update a single record:

Person result = (from p in Context.Persons
              where p.person_id == 5
              select p).SingleOrDefault();

result.is_default = false;

Context.SaveChanges();

and here's how you update multiple records:

List<Person> results = (from p in Context.Persons
                        where .... // add where condition here
                        select p).ToList();

foreach (Person p in results)
{
    p.is_default = false;
}

Context.SaveChanges();