Optimize Property Example (VJ++)

This example demonstrates the Field object dynamic Optimize property. The zip field of the Authors table in the Pubs database is not indexed. Setting the Optimize property to True on the zip field authorizes ADO to build an index that improves the performance of the Find method.

// BeginOptimizeJ
import com.ms.wfc.data.*;
import java.io.* ;

public class OptimizeX
{
   // The main entry point for the application.

   public static void main (String[] args)
   {
      OptimizeX();
      System.exit(0);
   }

   // OptimizeX function

   static void OptimizeX()
   {

      // Define ADO Objects.
      Recordset rstAuthors = null;

      // Declarations.
      BufferedReader in = 
         new BufferedReader (new InputStreamReader(System.in));
      String strCnn = "Provider='sqloledb';Data Source='MySqlServer';"
         + "Initial Catalog='Pubs';Integrated Security='SSPI';";

      try
      {
         rstAuthors = new Recordset();
         rstAuthors.setCursorLocation(AdoEnums.CursorLocation.CLIENT);
         // Enable index creation.
         rstAuthors.open("SELECT * FROM Authors",
               strCnn,
               AdoEnums.CursorType.STATIC,
               AdoEnums.LockType.READONLY,
               AdoEnums.CommandType.TEXT);
         rstAuthors.getField("zip").getProperties().
            getItem("Optimize").setBoolean(true); // Create the index.
         rstAuthors.find("zip = '94595'");   // Find Akiko Yokomoto.
         System.out.println(rstAuthors.getField("au_fname").getString() + 
            " " + rstAuthors.getField("au_lname").getString() + " " + 
            rstAuthors.getField("address").getString() + " " + 
            rstAuthors.getField("city").getString() + " " + 
            rstAuthors.getField("state").getString() + " ");
         rstAuthors.getField("zip").getProperties().
            getItem("Optimize").setBoolean(false); // Delete the index.

         System.out.println("\nPress <Enter> to continue..");
         in.readLine();
      }
      catch( AdoException ae )
      {
         // Notify user of any errors that result from ADO.

         // As passing a Recordset, check for null pointer first.
         if (rstAuthors != null)
         {
            PrintProviderError(rstAuthors.getActiveConnection());
         }
         else
         {
            System.out.println("Exception: " + ae.getMessage());
         }
      }

      // System read requires this catch.
      catch( java.io.IOException je)
      {
         PrintIOError(je);
      }   
      
      finally
      {
         // Cleanup objects before exit.   
         if (rstAuthors != null)
            if (rstAuthors.getState() == 1)
               rstAuthors.close();
      }
   }

   // PrintProviderError Function

   static void PrintProviderError( Connection Cnn1 )
   {
      // Print Provider errors from Connection object.
      // ErrItem is an item object in the Connections Errors collection.
      com.ms.wfc.data.Error  ErrItem = null;
      long nCount = 0;
      int  i      = 0;

      nCount = Cnn1.getErrors().getCount();

      // If there are any errors in the collection, print them.
      if( nCount > 0);
      {
         // Collection ranges from 0 to nCount - 1
         for (i = 0; i< nCount; i++)
         {
            ErrItem = Cnn1.getErrors().getItem(i);
            System.out.println("\t Error number: " + ErrItem.getNumber()
               + "\t" + ErrItem.getDescription() );
         }
      }

   }

   // PrintIOError Function

   static void PrintIOError( java.io.IOException je)
   {
      System.out.println("Error \n");
      System.out.println("\tSource = " + je.getClass() + "\n");
      System.out.println("\tDescription = " + je.getMessage() + "\n");
   }
}
// EndOptimizeJ

See Also

Field Object | Optimize Property—Dynamic (ADO)