Transaction Commit Doesn't Work

Could somebody also help me on the issue: I am using OLE DB to setup database with SQL CE 3.1, what i need is to flush the buffer to database file before program exit, I am using DBPROPVAL_SSCE_TCM_FLUSH and Transaction commit, but they don't work for me, My code is here:

1. the code to do transaction commit


// Access Transaction Interface

hr = pIDBCreateCommand->QueryInterface(IID_ITransactionLocal, (void **) &pTransLocal);

ULONG lTransLevel;

// Start the transaction

hr = pTransLocal->StartTransaction( ISOLATIONLEVEL_READCOMMITTED, 0, NULL, &lTransLevel );

// Execute the command with paramters.

hr = pICommandText->Execute(NULL, IID_NULL, &params, &cRowsAffected, NULL);

if( FAILED( hr ) )

{

goto Exit;

}

// commit

hr = pTransLocal->Commit( FALSE, XACTTC_SYNC, 0 );

pTransLocal->Release();



2. the code to set up property:


void LogDatabase::SetSessionProperty( IDBCreateSession *pISession )

{

DBPROPSET dbpropset[1]; // Property Set used to initialize provider

DBPROP sessionProps[1];

VariantInit(&sessionProps[0].vValue);

ISessionProperties *pISessionProperties = NULL;

//************** We Initial a session properties here *************

// Initialize a session object.

HRESULT hr = pISession->CreateSession(NULL, IID_ISessionProperties,

(IUnknown**) &pISessionProperties);

// Initialize the property to change commit mode.

sessionProps[0].dwPropertyID = DBPROP_SSCE_TRANSACTION_COMMIT_MODE;

sessionProps[0].dwOptions = DBPROPOPTIONS_REQUIRED;

sessionProps[0].vValue.vt = VT_I4;

sessionProps[0].vValue.lVal = DBPROPVAL_SSCE_TCM_FLUSH;



// Initialize the session property set.

dbpropset[0].guidPropertySet = DBPROPSET_SSCE_SESSION;

dbpropset[0].rgProperties = sessionProps;

dbpropset[0].cProperties = sizeof(sessionProps)/sizeof(sessionProps[0]);

// Set the session property.

hr = pISessionProperties->SetProperties(sizeof(dbpropset)/sizeof(dbpropset[0]),

dbpropset);

VariantClear(&sessionProps[0].vValue);

}