src/Importer.php
protected function applyId(& $row, $id, $identifierField)
    {
        $ids = (array) $id;
        $findId = function ($row) use ($ids, $identifierField) {
            foreach ($ids as $id) {
                // Foton == FOTON
                $bool = true;
                $identifierField = $this->flatten($identifierField);
                foreach ($identifierField as $identifier) {
                    $bool = $bool && (mb_strtolower($id[$identifier]) === mb_strtolower($row[$identifier]));
                }
                if ($bool) {
                    return $id['id'];
                }
            }
            return 0;
        };

        $isDeep = $this->isDeep($row);

        if ($isDeep) {
            foreach ($row as $i => & $r) {
                $r['id'] = $findId($r);
            }
        } else {
            $row['id'] = $findId($row);
        }
    }
protected function applyId(& $row, $id, $identifierField)
    {
        $ids = (array) $id;
        $findId = function ($row) use ($ids, $identifierField) {
            foreach ($ids as $id) {
                // Foton == FOTON
                $bool = true;
                $identifierField = $this->flatten($identifierField);
                foreach ($identifierField as $identifier) {
                    $bool = $bool && (mb_strtolower($id[$identifier]) === mb_strtolower($row[$identifier]));
                }
                if ($bool) {
                    return $id['id'];
                }
            }
            return 0;
        };

        $isDeep = $this->isDeep($row);

        if ($isDeep) {
            foreach ($row as $i => & $r) {
                $r['id'] = $findId($r);
            }
        } else {
            $row['id'] = $findId($row);
        }
    }
Apply inner DB id to row

@param $row
@param $id
@param $identifierField