private function getAttachmentStorageHash() { if (!$this->isAttachment()) { trigger_error("attachmentStorageHash can only be retrieved for attachment items", E_USER_ERROR); } if ($this->attachmentData['storageHash'] !== null) { return $this->attachmentData['storageHash']; } if (!$this->id) { return null; } $sql = "SELECT storageHash FROM itemAttachments WHERE itemID=?"; $stmt = Zotero_DB::getStatement($sql, true, Zotero_Shards::getByLibraryID($this->libraryID)); $val = Zotero_DB::valueQueryFromStatement($stmt, $this->id); $this->attachmentData['storageHash'] = $val; return $val; }