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.
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 = "DSN=Pubs;Provider=MSDASQL;uid=sa;pwd=;";
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();
// Cleanup objects before exit.
rstAuthors.close();
cnConn1.close();
}
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");
}
}