python - 如何扩展 `psycopg2.extras.DictCursor`？

Question

我想使用 python3-psycopg2 (2.5.4) 游标，它可以:

1)以类似字典的方式访问查询结果

2) 使用logging模块自动记录该游标执行的每条sql

我尝试了以下代码，它不起作用，我做错了什么？我可以扩展 psycopg2.extensions.cursor，但这不允许我执行 1)。

class LoggingCursor(psycopg2.extras.DictCursor):
    def __init__(self, *args, **kwargs):  # it didn't work with or
        super().__init__(*args, **kwargs) # without these 2 lines

    def execute(self, sql, args=None):
        from beautiful import app
        # logger = blah blah
        logger.debug(self.mogrify(sql, args).decode())
        psycopg2.extensions.cursor.execute(self, sql, args)

cursor = db_conn.cursor(cursor_factory=LoggingCursor)

当我cursor.execute(some_sql)时，它给了我:

File "some_file.py", line 123, in some_function
  some_var = cursor.fetchone()
File "/usr/local/lib/python3.4/dist-packages/psycopg2/extras.py", line 63, in fetchone
  res = super(DictCursorBase, self).fetchone()
File "/usr/local/lib/python3.4/dist-packages/psycopg2/extras.py", line 139, in __init__
  self._index = cursor.index

AttributeError: 'LoggingCursor' object has no attribute 'index'

Answer 1

改变一下怎么样

psycopg2.extensions.cursor.execute(self, sql, args)

至

super().execute(sql, args)

以便调用基类execute()方法？