Ejemplo de la propiedad Optimize (VJ++)

Se aplica a: Access 2013, Office 2013

En este ejemplo se muestra la propiedad dinámica Optimize de los objetos Field. El campo zip de la tabla Authors de la base de datos Pubs no está indexado. Al establecer la propiedad Optimize en True en el campo zip , ADO autoriza a crear un índice que mejore el rendimiento del método Find .

 
// 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