Update and CancelUpdate Methods Example (VJ++)
This example demonstrates the Update method in conjunction with the CancelUpdate method.
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=srv;"+
"Initial Catalog=Pubs;User Id=sa;Password=;";
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);
}
}
// 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=srv;"+
"Initial Catalog=Pubs;User Id=sa;Password=;";
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);
}
}
// 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");
}
}