def getall(self):
        try:
            spec = {'data': {'$exists': 1}}
            fields = {'_id': 0}
            sort = [('tid', 1)]
            cur = self.db.docs.find(spec, fields, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        return [Document(**row) for row in cur]
def downloadNewsPage(self, strTagName=None):
        if strTagName is None:
            #未指定 tag
            lstStrObtainedTagName = self.db.fetchallCompletedObtainedTagName()
            for strObtainedTagName in lstStrObtainedTagName:
                self.downloadNewsPageWithGivenTagName(strTagName=strObtainedTagName)
        else:
            #有指定 tag 名稱
            self.downloadNewsPageWithGivenTagName(strTagName=strTagName)