utils.py 文件源码

def __getitem__(self, key):
    # ====== multiple keys select ====== #
    if isinstance(key, (tuple, list, np.ndarray)):
      query = """SELECT value FROM {tb}
                       WHERE key IN {keyval};"""
      keyval = '(' + ', '.join(['"%s"' % str(k) for k in key]) + ')'
      self.cursor.execute(
          query.format(tb=self._current_table, keyval=keyval))
      results = self.cursor.fetchall()
      # check if any not found keys
      if len(results) != len(key):
        raise KeyError("Cannot find all `key`='%s' in the dictionary." % keyval)
      # load binary data
      results = [marshal.loads(r[0]) for r in results]
    # ====== single key select ====== #
    else:
      key = str(key)
      if key in self.current_cache:
        return self.current_cache[key]
      query = """SELECT value FROM {tb} WHERE key="{keyval}" LIMIT 1;"""
      results = self.connection.execute(
          query.format(tb=self._current_table, keyval=key)).fetchone()
      # results = self.cursor.fetchone()
      if results is None:
        raise KeyError("Cannot find `key`='%s' in the dictionary." % key)
      results = marshal.loads(results[0])
    return results