Optimize Property Example (VJ++)

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.

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 = "DSN=Pubs;Provider=MSDASQL;uid=sa;pwd=;";

        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.

            // Cleanup objects before exit.
            rstAuthors.close();
            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);
        }
    }

    // PrintProviderError Function

    static void PrintProviderError( Connection Cnn1 )
    {
        // Print Provider errors from Connection object.
        // ErrItem is an item object in the Connection’s 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");
    }
}