title: WCF ExtensionDataObject causes Entity Framework 4.2 to fail creating database
body: <p>I am trying to create a SQL CE 4.0 database using Entity Framework 4.2 and object first.</p>
  
  <p>My classes are defined in a WCF service.</p>
  
  <p>I have one base class:</p>
  
  <pre><code>public class BaseData
  {
      public DateTime LastUpdated { get; set; }
      public int StatusTypeId { get; set; }
      public StatusType StatusType { get; set; }
      public RecordStatusEnum RecordStatus { get; set; }
  }
  </code></pre>
  
  <p>and one inherited class:</p>
  
  <pre><code>public class JobType : BaseData
  {
      public int JobTypeId { get; set; }
      public string Name { get; set; }
      public string Description { get; set; }
      public int SortOrder { get; set; }
  
      public virtual ICollection&lt;Role&gt; Roles { get; set; }
  }
  </code></pre>
  
  <p>When the base class is serialized by WCF it adds an ExtensionDataObject property</p>
  
  <pre><code>    public partial class BaseData : object, System.Runtime.Serialization.IExtensibleDataObject, System.ComponentModel.INotifyPropertyChanged {
  
      [System.NonSerializedAttribute()]
      private System.Runtime.Serialization.ExtensionDataObject extensionDataField;
  
      [global::System.ComponentModel.BrowsableAttribute(false)]
      public System.Runtime.Serialization.ExtensionDataObject ExtensionData {
          get {
              return this.extensionDataField;
          }
          set {
              this.extensionDataField = value;
          }
      }
  </code></pre>
  
  <p>This causes EF to crash when creating a table from the JobType class with the following error:</p>
  
  <p>No mapping specified for properties JobType.ExtensionData in Set JobTypes</p>
  
  <p>How do I work around this? </p>