docs: def _get_all(self):
          ''' return all items
          '''
          rowid = 0
          while True:
              SQL_SELECT_MANY = 'SELECT rowid, * FROM %s WHERE rowid > ? LIMIT ?;' % self._table
              self._cursor.execute(SQL_SELECT_MANY, (rowid, ITEMS_PER_REQUEST))
              items = self._cursor.fetchall()
              if len(items) == 0:
                  break
              for item in items:
                  rowid = item['_id']
                  yield self._make_item(item)