Item Property Example (VJ++)

This example demonstrates how the Item property accesses members of a collection. The example opens the Authors table of the Pubs database with a parameterized command.

The parameter in the command issued against the database is accessed from the Command object's Parameters collection by index and name. Then the fields of the returned Recordset are accessed from that object's Fields collection by index and name.

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

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

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

   // ItemX  function

   static void ItemX()
   {

      // Define ADO Objects.
      Connection cnConn1 = null;
      Recordset rstAuthors = null;
      Command cmd = null;
      Parameter prm = null;
      Field fld = null;

      // Declarations.
      BufferedReader in = 
         new BufferedReader (new InputStreamReader(System.in));
      String strCnn = "Provider='sqloledb';Data Source='MySqlServer';" +
            "Initial Catalog='Pubs';Integrated Security='SSPI';";
      Variant [] varColumn = null;
      int intIndex;
      int intLimit;

      try
      {
         cnConn1 = new Connection();
         rstAuthors = new Recordset();
         cmd = new Command();

         //  Set the array with the Authors table field (column) names.
         varColumn = new Variant[9];
         varColumn[0] = new Variant("au_id");
         varColumn[1] = new Variant("au_lname");
         varColumn[2] = new Variant("au_fname");
         varColumn[3] = new Variant("phone");
         varColumn[4] = new Variant("address");
         varColumn[5] = new Variant("city");
         varColumn[6] = new Variant("state");
         varColumn[7] = new Variant("zip");
         varColumn[8] = new Variant("contract");

         cmd.setCommandText("SELECT * FROM Authors WHERE state = ?");
         prm = cmd.createParameter("ItemXparm",
                             AdoEnums.DataType.CHAR,
                             AdoEnums.ParameterDirection.INPUT,
                             2,
                             "CA");
         cmd.getParameters().append(prm);

         cnConn1.open(strCnn);
         cmd.setActiveConnection(cnConn1);

         // Connection and CommandType are omitted
         // because a Command Object is provided.
         rstAuthors.open(cmd,
                null ,
                AdoEnums.CursorType.STATIC,
                AdoEnums.LockType.READONLY);

         System.out.println(
            "The Parameters collection accessed by index...");
         prm = cmd.getParameters().getItem(0);
         System.out.println("Parameter name = '" +
                        prm.getName() +
                        "', value = '" +
                        prm.getValue().toString() + "'\n");

         System.out.println(
            "The Parameters collection accessed by name...");
         prm = cmd.getParameters().getItem("ItemXparm");
         System.out.println("Parameters name = '" +
                        prm.getName() +
                        "', value = '" +
                        prm.getValue().toString() + "'\n");
         System.out.println("Press <Enter> to continue..");
         in.readLine();

         System.out.println(
            "The Fields collection accessed by index...");
         rstAuthors.moveFirst();
         intLimit = rstAuthors.getFields().getCount() - 1;
         for(intIndex = 0; intIndex <= intLimit; intIndex++)
         {
            fld = rstAuthors.getFields().getItem(intIndex);
            short intVtType = fld.getValue().getvt();
            String strFieldValue;
            switch(intVtType)
            {
            case Variant.VariantString :
               strFieldValue = fld.getValue().toString();
               break;
            case Variant.VariantBoolean :
               if(fld.getValue().getBoolean())
                  strFieldValue = "True";
               else
                  strFieldValue = "False";
               break;
            default :
               strFieldValue = fld.getValue().toString();
               break;
            }
            System.out.println("Field " +
                           Integer.toString(intIndex) +
                           " : Name = '" +
                           fld.getName() +
                           "', value = '" +
                           strFieldValue +
                           "'");
         }
         System.out.println("\nPress <Enter> to continue..");
         in.readLine();

         System.out.println("The Fields collection accessed by name...");
         rstAuthors.moveFirst();
         for(intIndex = 0; intIndex <= 8; intIndex++)
         {
            fld = rstAuthors.getFields().getItem
               (varColumn[intIndex].toString());
            short intVtType = fld.getValue().getvt();
            String strFieldValue;
            switch(intVtType)
            {
            case Variant.VariantString :
               strFieldValue = fld.getValue().toString();
               break;
            case Variant.VariantBoolean :
               if(fld.getValue().getBoolean())
                  strFieldValue = "True";
               else
                  strFieldValue = "False";
               break;
            default :
               strFieldValue = fld.getValue().toString();
               break;
            }
            System.out.println("Field " +
                           "name = '" +
                           fld.getName() +
                           "', value = '" +
                           strFieldValue +
                           "'");
         }
         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();  
         if (cnConn1 != null)
            if (cnConn1.getState() == 1)
               cnConn1.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");
   }
}
// EndItemJ

See Also

Command Object | Fields Collection | Item Property | Parameters Collection | Recordset Object