Following is the error message I get:

> 
> Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. See <http://go.microsoft.com/fwlink/?LinkId=472540> for information on understanding and handling optimistic concurrency exceptions.
> 
> 
> 

My model consists of few columns, among them two columns which make up the primary key clustered:

```
[Key]
[Column(Order = 0)]
public string SourceName { get; set; }
[Key]
[Column(Order = 1)]
public string SourceType { get; set; }

```

Code to update using Entity Framework:

```
 _Entities.SourceInfoes.Attach(entity);
 _Entities.Entry(entity).State = EntityState.Modified;
 _Entities.SaveChanges();

```

Can some one help me on how to solve the exception above?