title: How do I handle UpdateException - 'Violation of PRIMARY KEY constraint' on Entity Framework?
body: <p>I have an appication that allows multiple users and a database table which has 2 IDs as a compound key. These IDs are also foreign keys from another table.
  So when 2 users try to add an entry to this tabel with the same IDs one of them gets an UpdateException because of Primary Key constaint violation.
  I already found out that it should be handled like this:</p>
  
  <pre><code>try
  {
      result = base.SaveChanges(options);
  }
  catch (UpdateException ex)
  {
      SqlException innerException = ex.InnerException as SqlException;
      if (innerException != null &amp;&amp; innerException.Number == 2627 || innerException.Number == 2601)
      {
          // handle here
      }
      else
      {
          throw;
      }
  }
  </code></pre>
  
  <p>But what do I actually do on the "//Handle here" part. I tried refreshing the object but it is in the "Added" state and therefor can not be refreshed.
  What I whant it to do is: Acknowledge that there is already an object with these IDs, drop its object that it wanted to insert and load the existing object from the database.
  How can I do that?</p>