private function removeNullValues(array $record)
    {
        // 值为NULL的字段不用缓存
        foreach ($record as $key => $val) {
            if ($val === null) {
                unset($record[$key]);
            }
        }

        return $record;
    }
private function removeNullValues(array $record)
    {
        // 值为NULL的字段不用缓存
        foreach ($record as $key => $val) {
            if ($val === null) {
                unset($record[$key]);
            }
        }

        return $record;
    }
private function removeNullValues ( array $ record ) { // 值为NULL的字段不用缓存 foreach ( $ record as $ key => $ val ) { if ( $ val === null ) { unset ( $ record [ $ key ] ) ; } } return $ record ; }
remove NULL value from record.

@param array $record

@return array
remove NULL value from record .