title: Filtering A TClientDataSet On A NestedDataSet Field
body: <p>I have a small application I am working on that is almost finished thanks to 
  those who have assisted me here.  I have one last task however.
  I need to be able to Filter a TClientDataSet on a NestedDataSet field.</p>
  
  <pre><code>ClientDataset1
  Field0: Name (Lake Name)
  ClientDataset2
  Field0: Species (Fish Species)
  
  type
    TDataModule1 = class( TDataModule )
      ClientDataSet1: TClientDataSet;
      ClientDataSet2: TClientDataSet;
      ClientDataSet1Name: TStringField;
      ClientDataSet1County: TStringField;
      ClientDataSet1Town: TStringField;
      ClientDataSet1Area: TStringField;
      ClientDataSet1MaximumDepth: TStringField;
      ClientDataSet1MeanDepth: TStringField;
      ClientDataSet1MapFilename: TStringField;
      ClientDataSet1Species: TDataSetField;
      ClientDataSet2Species: TStringField;
      procedure DataModuleDestroy( Sender: TObject );
    private
      { Private declarations }
    public
      { Public declarations }
    end;
  
  Data:
  Nate Pond
      Brook trout
      Creek chub
      Golden shiner
  Black Pond
      Brook trout
      Brown bullhead
      Common shiner
  Lake Placid
      Lake trout
      Smallmouth bass
      Yellow perch
  </code></pre>
  
  <p>I need to to filter ClientDataset1 to show all lakes that have Brook trout 
  in the ClientDataset Species field.</p>
  
  <pre><code>Filtered:
  Nate Pond
      Brook trout
      Creek chub
      Golden shiner
  Black Pond
      Brook trout
      Brown bullhead
      Common shiner
  </code></pre>
  
  <p>How can a filter (or other means) be created to accomplish this?
  Are there any third-party componets that will do this?</p>
  
  <p>Thanks,</p>
  
  <p>Bill</p>