Update specific property using EF

Question

I had to update single field in my database using EF. I am doing as it like this:

1 - Load the orginal record from table based on name

2 - Update the field value

3 - save the object back to db

Code:

public void UpdateUser(List<User> users)
{
    foreach (User user in users)
    {
        Job original = _context.Users.Where(x => x.Name == user.Name).AsNoTracking().FirstOrDefault();
        if (original != null)
        {                   
            original.Name = user.Nanme;
            _context.Entry(original).State = EntityState.Modified; // not sure it is needed or not
        }
        _context.SaveChanges();           

    }
}

Is it an efficient way? Or i can do it in much better way?

Divyang Desai · Answer 1 · 2016-10-15T05:35:46.807

0

Load the original record from table based on name.

This is not really a good practices, you should get record based on id

  Job original = _context.Users.Where(x => x.id== user.id).AsNoTracking().FirstOrDefault();

And _context.SaveChanges(); should be out side of foreach, so update will perform once.

Here you need _context.Entry(original).State = EntityState.Modified;, which indicates the entity is being tracked by the context and exists in the database, and some or all of its property values have been modified.

So finally your code looks like:

foreach (User user in users)
{
  Job original = _context.Users.Where(x => x.id== user.id).AsNoTracking().FirstOrDefault();
  if (original != null)
  {                   
    original.Name = user.Nanme;
   _context.Entry(original).State = EntityState.Modified;
  }                      
}
 _context.SaveChanges();

Hope this helps!

edited Oct 15 '16 at 05:35

answered Oct 15 '16 at 05:15

Divyang Desai

7,483
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EF does no have track of `original` entity and without attaching the entity, `original` won't update. – Mohsen Esmailpour Oct 15 '16 at 05:28
You said the same what i did. How is it different? – simbada Oct 15 '16 at 08:39
@simbada, *How is it different* Read the answer already explain. – Divyang Desai Oct 15 '16 at 08:44
@simbada, *Is it an efficient way?* This is general way, look at [this](http://stackoverflow.com/a/21592733/4753489) – Divyang Desai Oct 15 '16 at 08:55
@simbada And one more thing, look at your first line *update single field in my database* if you want to update single filed then not need to `foreach` just fetch single record by `Id` and updated it. – Divyang Desai Oct 15 '16 at 09:02

score 0 · Answer 2 · answered Oct 15 '16 at 05:52

0

How about this,

foreach (User user in users)
{
  _context.Users.Find(user.id).Name = user.Name;
}                      
_context.SaveChanges();

answered Oct 15 '16 at 05:52

Awais Mahmood

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Update specific property using EF

2 Answers2