How to Update only single field using EF

Question

This is the current basic code :

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Edit(Registration registration)
    {
        if (ModelState.IsValid)
        {
            db.Entry(registration).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        return View(registration);
    }

I have around 15 fields in Registration table , how ever i just want to update the "Date" field , the object that i receive here is "registration" which only has value for a date , but the current code updates all the entries , what i want is to just update the "Date" field , whose value i have got in "registration"

Help would be much appreciated :)

Anthony Chu · Answer 1 · 2014-04-30T05:57:21.807

6

Attach it to the context in the Unchanged state, and only set Date as modified.

if (ModelState.IsValid)
{
    db.Registrations.Attach(registration); // attach in the Unchanged state
    db.Entry(registration).Property(r => r.Date).IsModified = true;
    // Date field is set to Modified (entity is now Modified as well)
    db.SaveChanges();
    return RedirectToAction("Index");
}

You said the incoming entity only has Date filled in, hopefully there's an Id too. :)

edited Apr 30 '14 at 05:57

answered Apr 30 '14 at 05:45

Anthony Chu

37,170
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yes there is an id , is .Attach a method tht comes with EF? or it has to be made? coz db.Attach(registration); is giving error saying that this method needs to be created – ZaraQ Apr 30 '14 at 05:55
Sorry, the `Attach()` method is on the `DbSet` itself. Corrected. – Anthony Chu Apr 30 '14 at 05:57
Thanx a bunch :) mission accomplished :) – ZaraQ Apr 30 '14 at 07:05

score 1 · Answer 2 · edited May 23 '17 at 12:22

1

Try this

if (ModelState.IsValid)
        {
            db.Entry(registration).State = EntityState.Modified;
            db.Entry(registration).Property(x => x.Name).IsModified = false; //Add fields which you don't want to modify
            db.SaveChanges();
            return RedirectToAction("Index");
        }

Update : as per answer in this post

var excluded = new[] { "property1", "property2" };
var entry = context.Entry(obj);
entry.State = EntityState.Modified;
foreach (var name in excluded)
{
    entry.Property(name).IsModified = false;
}

edited May 23 '17 at 12:22

Community

1
1

answered Apr 30 '14 at 05:41

Nilesh Gajare

6,302
3
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73

according to this i'll have to manually exclude a number of records , like around 14 , cant i just mention one property that i have to update? something like below : UPDATE dbo.registrations SET Date = registration WHERE id = registrations.id -- i don't care about the other fields – ZaraQ Apr 30 '14 at 05:47

score 1 · Answer 3 · answered May 04 '14 at 07:48

1

Registration registor =db.Registration.First(f=>RegistrationId==RegistrationId);
registor.Date = registration.Date;
db.SaveChanges();

use this for single record updation and i assuming that RegistrationId in your Registration table.

answered May 04 '14 at 07:48

Shahzad Khan

432
2
14

How to Update only single field using EF

3 Answers3

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