How to add a ring tone for a specific contact stored in contacts database.

void AddRingtoneForContactL(const TDesC& aRingtone,TContactItemId aId)
{
    CContactDatabase* ContactDb = CContactDatabase::OpenL();   
    CleanupStack::PushL(ContactDb);
   
    CContactItem* SelItem = ContactDb->OpenContactL(aId);
    CleanupStack::PushL(SelItem);
   
    TInt RIndex = SelItem->CardFields().Find(KUidContactFieldRingTone);

    if (RIndex != KErrNotFound)
    {
        SelItem->RemoveField(RIndex);
    }

    CContactItemField* contactField = CContactItemField::NewLC(KStorageTypeText,KUidContactFieldRingTone);
   
    contactField->TextStorage()->SetTextL(aRingtone);
   
    contactField->SetLabelL(_L("tone"));
    contactField->SetMapping(KUidContactFieldVCardMapUnknown);
   
    contactField->SetId(2);

    SelItem->AddFieldL(*contactField);
    CleanupStack::Pop();//ContactField       
    ContactDb->CommitContactL(*SelItem);
   
    CleanupStack::PopAndDestroy(2);//ContactDb,SelItem
}