Cancel Method

Applies To

Description

This method is called to cancel a non-blocking operation that is underway on the OSqlStmt object. Valid only if the OSqlStmt object has been created with OSQLSTMT_NONBLK option.

Usage

oresult Cancel(void) const

Arguments

none

Remarks

The application can cancel a long running asynchronous operation by calling the Cancel method on the OSqlStmt object. The Cancel method will cancel the execution that is in progress.

Return Values

An oresult indicating whether the operation succeeded (OSUCCESS) or not (OFAILURE).

Errors are thrown as exceptions.

Example

This example uses try and catch blocks.

//try block

try

{

long ret;

OStartup(OSTARTUP_MULTITHREADED);

osess.Open();

odb.Open(osess, "ExampleDB", "scott", "tiger");

if ( ! odb.IsOpen() )

{

cout << "Database not opened: " << odb.GetErrorText() <<

endl;

odb.Close();

return(-1);

}

// To cancel an asynchronous execution

OSqlStmt osqlstmt(odb, "update junk set ichar='CANCEL' where iint

100" ,OSQLSTMT_NONBLK);

if ( ret != OSQL_SUCCESS )

cout << "Error " << osqlstmt.GetErrorText() << endl;

ret = osqlstmt.NonBlockingState();

if ( ret == OSQL_STILL_EXECUTING )

{

ret = osqlstmt.Cancel();

if ( ret != OSQL_SUCCESS )

cout << "Error " << osqlstmt.GetErrorText() << endl;

else

cout << "Cancel of non-block execution succesful" <<

endl;

}

//catch block

catch(OException oerr)

{

cout << "Exception while executing non-blocking mode : " <<
oerr.GetErrorText() << endl;

retVal = -1;

}

Additional examples can be found in ORACLE_BASE\ORACLE_HOME\oo4o\cpp. See About Sample Code and Applications.