WCF Data Service Error : Update Mapping not found for EntitySet 'Products'

Root Cause : There was a problem with Mapping in EDMX , I created an extra field that was not mapped to any table

  <message>Update Mapping not found for EntitySet 'Products'.</message>
    <type>System.Data.UpdateException</type>
    <stacktrace>   at System.Data.Mapping.Update.Internal.UpdateTranslator.&lt;ProduceDynamicCommands&gt;d__0.MoveNext()&#xD;
   at System.Linq.Enumerable.&lt;ConcatIterator&gt;d__71`1.MoveNext()&#xD;
   at System.Data.Mapping.Update.Internal.UpdateCommandOrderer..ctor(IEnumerable`1 commands, UpdateTranslator translator)&#xD;
   at System.Data.Mapping.Update.Internal.UpdateTranslator.ProduceCommands()&#xD;
   at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)&#xD;
   at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)&#xD;
   at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)&#xD;
   at System.Data.Services.Providers.ObjectContextServiceProvider.SaveChanges()&#xD;
   at System.Data.Services.DataService`1.HandleNonBatchRequest(RequestDescription description)&#xD;
   at System.Data.Services.DataService`1.HandleRequest()</stacktrace>
  </innererror>
</error>
       Source=System.Data.Services.Client
       StatusCode=500
       StackTrace:
            at System.Data.Services.Client.DataServiceContext.SaveResult.<HandleBatchResponse>d__1e.MoveNext()
       InnerException: