Question

What I want to do is append to a record’s note column.

What I do not want to do is fetch the whole record, which is very significant.

Here’s code that does not work:

string AppendNote(int key, string note)
{
    using (MyEntities _Context = new MyEntities())
    {
        var _Record = _Context.Records
            .Where(x => x.Id == key)
            .Select(x => new Record { Id = x.Id, Notes = x.Notes })
            .First();
        _Record.Notes += note;
        _Context.SaveChanges();
    }
}

What is the correct way?

I realize it is very similar to this VERY OLD question: Update statement with Entity Framework and this similar but ultimately dissimilar question: How to update a record without selecting that record again in ADO.NET Entity Framework? but, still, it seems there has to be a way.

Answer 1

As for simple minimal updates in EF, you can do them by attaching an object to the context like this:

string AppendNote(int key, string note)
{
    using (MyEntities _Context = new MyEntities())
    {
        var _Record = new Record { Id = key };
        _Context.Entry(_Record).State = System.Data.EntityState.Unchanged;
        _Record.Notes = note; //a simple update
        _Context.SaveChanges();
    }
}

However, you want to append to a current value. The code below is a bit messy because of the anonymously typed variable _R but it should fetch just the Notes column and append to it:

string AppendNote(int key, string note)
{
    using (MyEntities _Context = new MyEntities())
    {
        var _R = _Context.Records
            .Select(x=>new {Id = x.Id, Notes=x.Notes})
            .Where(x=>x.Id == key)
            .First();
        var _Record = new Record { Id = _R.Id, Notes=_R.Notes };
        _Context.Entry(_Record).State = System.Data.EntityState.Unchanged;
        _Record.Notes+= note;
        _Context.SaveChanges();
    }
}