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Groups > comp.lang.python > #86150

Re: try pattern for database connection with the close method

References <6trfeate2ppvm1mcapgr0g4g2fd3vceab6@4ax.com> <mailman.18955.1424521415.18130.python-list@python.org> <mk8keahatht34gt0kq1ncmtaskdu2s3arc@4ax.com>
Date 2015-02-22 13:15 -0600
Subject Re: try pattern for database connection with the close method
From Skip Montanaro <skip.montanaro@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.19025.1424633976.18130.python-list@python.org> (permalink)

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On Sun, Feb 22, 2015 at 12:41 PM, Mario Figueiredo <marfig@gmail.com> wrote:
> The sqlite context manager doesn't close a database connection on
> exit. It only ensures, commits and rollbacks are performed.

Sorry, I haven't paid careful attention to this thread, so perhaps
this has already been suggested, however... Can't you write your own
class which delegates to the necessary sqlite3 bits and has a context
manager with the desired behavior? Thinking out loud, you could define
a ConnectionMgr class which accepts a sqlite3 connection as a
parameter:

class ConnectionMgr(object):
  def __init__(self, conn):
    self.conn = conn

  def __enter__(self):
    ...

  def __exit__(self, type, value, exception):
    if self.conn is not None:
      ... close self.conn connection here ...
    self.conn = None

  def __getattr__(self, attr):
    return getattr(self.conn, attr)

then...

  try:
    with MyConnection(lite.connect('data.db')) as db:
      ...
  except lite.DatabaseError:
    ...

Might also have to __enter__ and __exit__ self.conn as appropriate.

Skip

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Thread

try pattern for database connection with the close method Mario Figueiredo <marfig@gmail.com> - 2015-02-21 03:42 +0100
  Re: try pattern for database connection with the close method Chris Kaynor <ckaynor@zindagigames.com> - 2015-02-20 18:59 -0800
  Re: try pattern for database connection with the close method Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-21 12:22 +0000
    Re: try pattern for database connection with the close method Mario Figueiredo <marfig@gmail.com> - 2015-02-22 19:41 +0100
      Re: try pattern for database connection with the close method Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-22 19:07 +0000
        Re: try pattern for database connection with the close method Mario Figueiredo <marfig@gmail.com> - 2015-02-23 00:25 +0100
      Re: try pattern for database connection with the close method Skip Montanaro <skip.montanaro@gmail.com> - 2015-02-22 13:15 -0600
        Re: try pattern for database connection with the close method Mario Figueiredo <marfig@gmail.com> - 2015-02-23 00:30 +0100
  Re: try pattern for database connection with the close method Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-21 08:16 -0700
  Re: try pattern for database connection with the close method Peter Otten <__peter__@web.de> - 2015-02-21 16:22 +0100
    Re: try pattern for database connection with the close method Mario Figueiredo <marfig@gmail.com> - 2015-02-23 00:35 +0100
  Re: try pattern for database connection with the close method Peter Otten <__peter__@web.de> - 2015-02-21 16:27 +0100
  Re: try pattern for database connection with the close method Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-21 08:50 -0700
  Re: try pattern for database connection with the close method Peter Otten <__peter__@web.de> - 2015-02-21 18:02 +0100

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