Delete entity in EF4 without loading the entire entity

I am using entity framework 4 and have the following setup and problem.

I have a table in MySql with metadata fields an a blob field. Using the Table Splitting technique described here i have divided the table into two entities (DataItem and DataItemDetails). This way I can load all the metadata without loading the blobs.

Problem is that when I try to delete a dataitem entity I get this exception:

exception: System.Data.UpdateException: Invalid data encounter开发者_如何学运维ed. A required relationship is missing. Examine StateEntries to determine the source of the constraint violation.

If I turn of Lazy Loading or load the DataItemDetail part i can delete the DataItem.

This is OK, but I don't want to load the data just to delete it.

if (!D.DataItemDetailReference.IsLoaded)
     D.DataItemDetailReference.Load();
_db.DataItems.DeleteObject(d);
_db.SaveChanges();


_db is the ObjectContext dereived class and D is an instance of the DataItem class.

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If you don't want to load the property you must trick EF so it thinks that the related DataItemDetail is loaded.

var detailItem = new DataItemDetail { Id = d.Id }; 
_db.DataItemDetails.Attach(detailItem);
_db.DataItems.DeleteObject(d);
_db.SaveChanges();

The problem here is that table splitting uses 1:1 relation and EF knows that if it deletes one end of the relation it should also delete other end but because you didn't load other end it can't do it.

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Thanks Ladislav and Markus! This is exactly what I needed. To do this in Entity Framework 4.1 with Database First, I had to change it thusly:

If _db.Entry(d).Reference(Function(e) e.DataItemDetails).IsLoaded() = False Then
     Dim detailItem = New DataItemDetails With { .ID = d.ID }
     _db.DataItemDetails.Attach(detailItem)
End If
_db.DataItems.Remove(d)
_db.SaveChanges()

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Is there any reason you can't make a call to a stored proc? MEF should handle those okay, and you'd be fine & fast to pass an ID to a stored proc where you can do what you like with the data.

Sorry...edit to say, I know this doesn't answer the question "how to with EF4", but if you're stuck this is a fairly viable work around (and easy to implement, too). Cheers.