Delete Method Example (VJ++)

This example uses the Delete method to remove a specified record from a Recordset.

// BeginDeleteJ
// The WFC class includes the ADO objects.

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

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

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

   // DeleteX function

   static void DeleteX()
   {

      // Define ADO Objects.
      Recordset rstRoySched = null;

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

      String  strMessage="";
      String  strTitleID;
      int intLoRange =0;
      int intHiRange =0;
      int intRoyalty =0;
      boolean bolFound;

      try
      {
         rstRoySched = new Recordset();
         rstRoySched.setCursorLocation(AdoEnums.CursorLocation.CLIENT);
         rstRoySched.setCursorType(AdoEnums.CursorType.STATIC);
         rstRoySched.setLockType(AdoEnums.LockType.BATCHOPTIMISTIC);

         // Open RoySched table.
         rstRoySched.open("SELECT * FROM roysched " +
            "WHERE royalty = 20", strCnn,
            AdoEnums.CursorType.STATIC,
            AdoEnums.LockType.BATCHOPTIMISTIC,
            AdoEnums.CommandType.TEXT);

         // Prompt for a record to delete.
         strMessage = "Before delete there are "
            + rstRoySched.getRecordCount()
            + " titles with 20 percent royalty:" + "\n\n";
         while(!rstRoySched.getEOF())
         {
            strMessage += rstRoySched.getField("title_id").getString() + 
               "\n\n";
            rstRoySched.moveNext();
         }
         strMessage += "Enter the ID of a record to delete:" + "\n";
         System.out.println(strMessage);
         strTitleID = in.readLine().trim().toUpperCase();

         // Move to the record and save data so it can be restored.
         rstRoySched.setFilter("title_id = '" + strTitleID + "'");
         if(!(rstRoySched.getRecordCount()==0))
         {
            intLoRange = rstRoySched.getField("lorange").getInt();
            intHiRange = rstRoySched.getField("hirange").getInt();
            intRoyalty = rstRoySched.getField("royalty").getInt();
            bolFound = true;
         }
         else
         {
            System.out.println("\nIncorrect ID. No Record deleted." );
            bolFound = false;
         }

         // Delete the record.
         if(bolFound)
         {
            rstRoySched.delete();
            rstRoySched.updateBatch();
         }
         // Show the results.
         rstRoySched.setFilter(new Integer(AdoEnums.FilterGroup.NONE));
         rstRoySched.requery();
         strMessage ="";
         strMessage = "\n\nAfter delete there are "
            + rstRoySched.getRecordCount()
            + " titles with 20 percent royalty:" + "\n\n";
         while(!rstRoySched.getEOF())
         {
            strMessage += rstRoySched.getField("title_id").getString() + 
               "\n\n";
            rstRoySched.moveNext();
         }
         System.out.println(strMessage);
         System.out.println("\nPress <Enter> to continue..");
         in.readLine();

         // Restore the data because this is a demonstration.
         if(bolFound)
         {
            rstRoySched.addNew();
            rstRoySched.getField("title_id").setString(strTitleID);
            rstRoySched.getField("lorange").setInt(intLoRange);
            rstRoySched.getField("hirange").setInt(intHiRange);
            rstRoySched.getField("royalty").setInt(intRoyalty);
            rstRoySched.updateBatch();
         }
      }
      catch( AdoException ae )
      {
         // Notify user of any errors that result from ADO.

         // As passing a Recordset, check for null pointer first.
            if (rstRoySched != null)
            {
               PrintProviderError(rstRoySched.getActiveConnection());
               System.out.println("Exception: " + ae.getMessage());
            }
            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 (rstRoySched != null)
            if (rstRoySched.getState() == 1)
               rstRoySched.close();
      }

   }

   // 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");
   }
}

// EndDeleteJ

See Also

Delete Method (ADO Recordset) | Recordset Object