Update and CancelUpdate Methods Example (VJ++)

This example demonstrates the Update method in conjunction with the CancelUpdate method.

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

public class UpdateX
{
   // The main entry point of the application.

   public static void main (String[] args)
   {
      UpdateX();
      UpdateX2();
      System.exit(0);
   }
   // UpdateX Function

   static void UpdateX()
   {
      // Define ADO objects.
      Recordset rstEmployees = null;

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

      try
      {
         // Open Recordset with names from Employees table.
         rstEmployees = new Recordset();
         rstEmployees.setCursorType(AdoEnums.CursorType.KEYSET);
         rstEmployees.setLockType(AdoEnums.LockType.OPTIMISTIC);
         rstEmployees.open("SELECT fname,lname FROM Employees " +
            "ORDER BY lname", strCnn, AdoEnums.CursorType.KEYSET, 
            AdoEnums.LockType.OPTIMISTIC, AdoEnums.CommandType.TEXT);

         // Store Original data.
         strOldFirst = rstEmployees.getField("fname").getString();
         strOldLast = rstEmployees.getField("lname").getString();

         // Change data in edit buffer.
         rstEmployees.getField("fname").setString("Linda");
         rstEmployees.getField("lname").setString("Kobara");

         // Show contents of buffer and get user input.
         strMessage = "Edit in Progress :\n" +
            "\tOriginal Data = " + strOldFirst + "  " + strOldLast +
            "\n\tData in Buffer = " + 
            rstEmployees.getField("fname").getString() + " " + 
            rstEmployees.getField("lname").getString() + "\n\n" +
             "Use Update to replace the original data with " +
            "the buffered data in the Recordset?Enter (Y/N)";

         System.out.println(strMessage);
         if(in.readLine().trim().equalsIgnoreCase("Y"))
            rstEmployees.update();
         else
            rstEmployees.cancelUpdate();

         // Show the resulting data.
         System.out.println("Data in Recordset = " + 
            rstEmployees.getField("fname").getString() +
            "  " + rstEmployees.getField("lname").getString()+ "\n");

         // Restore original data because this is a demonstration.
         if(!(strOldFirst.equals(
            rstEmployees.getField("fname").getString()) && 
            strOldLast.equals(
            rstEmployees.getField("lname").getString())))
         {
            rstEmployees.getField("fname").setString(strOldFirst);
            rstEmployees.getField("lname").setString(strOldLast);
            rstEmployees.update();
         }
         // Cleanup Objects before exit.
         rstEmployees.close();

         System.out.println("Press <Enter> to continue..");
         in.readLine();

      }
      catch(AdoException ae)
      {
         // Notify the user of any errors that result from ADO.

         // As passing a recordset, check for null pointer first.
         if(rstEmployees != null)
         {
            PrintProviderError(rstEmployees.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 (rstEmployees != null)
            if (rstEmployees.getState() == 1)
               rstEmployees.close();
      }
   }
   // UpdateX2 Function

   static void UpdateX2()
   {
      // This example demonstrates the Update method in conjunction
      // with the AddNew method.

      // Define ADO Objects.
      Connection cnn1 = null;
      Recordset rstEmployees = null;

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

      try
      {
         // Open a connection.
         cnn1 = new Connection();
         cnn1.open(strCnn);

         // Open Recordset with data from Employees table.
         rstEmployees = new Recordset();
         rstEmployees.setCursorType(AdoEnums.CursorType.KEYSET);
         rstEmployees.setLockType(AdoEnums.LockType.OPTIMISTIC);
         rstEmployees.open("employee", cnn1, AdoEnums.CursorType.KEYSET, 
            AdoEnums.LockType.OPTIMISTIC, AdoEnums.CommandType.TABLE);

         rstEmployees.addNew();
         strEmpID="B-S55555M";
         rstEmployees.getField("emp_id").setString(strEmpID);
         rstEmployees.getField("fname").setString("Bill");
         rstEmployees.getField("lname").setString("Sornsin");

         // Show contents of buffer and get user input.
         strMessage = "AddNew in progress : " + "\n" +
            "\tData in Buffer = " + 
            rstEmployees.getField("emp_id").getString() +
            "  " + rstEmployees.getField("fname").getString() + "  " +
            rstEmployees.getField("lname").getString()+ "\n\n" +
            "Use Update to save buffer to recordset?Enter (Y/N)";
         System.out.println(strMessage);
         if(in.readLine().trim().equalsIgnoreCase("Y"))
         {
            rstEmployees.update();
            // Go to the new record and show the resulting data.
            System.out.println("Data in recordset = " + 
               rstEmployees.getField("emp_id").getString()+
               "  " + rstEmployees.getField("fname").getString() +
               "  " + rstEmployees.getField("lname").getString() + "\n");
         }
         else
         {
            rstEmployees.cancelUpdate();
            System.out.println("No new Record added.\n");
         }
         // Delete new data because this is a demonstration.
         cnn1.execute(
            "DELETE FROM employee WHERE emp_id='" + strEmpID +"'");

         // Cleanup Objects before exit
         rstEmployees.close();

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

         // As passing a recordset, check for null pointer first.
         if(rstEmployees != null)
         {
            PrintProviderError(rstEmployees.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 (rstEmployees != null)
            if (rstEmployees.getState() == 1)
               rstEmployees.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("\t Source: " + je.getClass() + "\n");
      System.out.println("\t Description: "+ je.getMessage() + "\n");
   }
}
// EndUpdateJ

See Also

CancelUpdate Method | Update Method