function __delRateFromCache($from, $to)
 {
     global $application;
     $tables = $this->getTables();
     $rc_table = $tables['cconv_rates_cache']['columns'];
     $query = new DB_Delete('cconv_rates_cache');
     $query->addWhereOpenSection();
     $query->WhereValue($rc_table['from'], DB_EQ, $from);
     $query->WhereAnd();
     $query->WhereValue($rc_table['to'], DB_EQ, $to);
     $query->addWhereCloseSection();
     $query->WhereOR();
     $query->addWhereOpenSection();
     $query->WhereValue($rc_table['from'], DB_EQ, $to);
     $query->WhereAND();
     $query->WhereValue($rc_table['to'], DB_EQ, $from);
     $query->addWhereCloseSection();
     $application->db->getDB_Result($query);
     return;
 }