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Groups > comp.lang.python > #86008

Re: try pattern for database connection with the close method

References <6trfeate2ppvm1mcapgr0g4g2fd3vceab6@4ax.com>
From Chris Kaynor <ckaynor@zindagigames.com>
Date 2015-02-20 18:59 -0800
Subject Re: try pattern for database connection with the close method
Newsgroups comp.lang.python
Message-ID <mailman.18943.1424488028.18130.python-list@python.org> (permalink)

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On Fri, Feb 20, 2015 at 6:42 PM, Mario Figueiredo <marfig@gmail.com> wrote:
>         import sqlite3 as lite
>
>         try:
>             db = lite.connect('data.db')
>         except lite.DatabaseError:
>             raise OSError('database file corrupt or not found.')
>         else:
>             try:
>                 with db:
>                     db.execute(sql, parms)
>             except lite.IntegrityError:
>                 raise ValueError('invalid data')
>             finally:
>                 db.close()

Two comments:

You could remove the "else" statement, as it will work exactly the same
with or without it. This will reduce the indentation of the bulk of the
code by 1 level.
You MIGHT be able to remove the finally...close as the with-statement
probably does the same thing. I do not know sqlite3, however, so it may do
something different, such as committing, but that would normally be on some
transition object you get from a call.

Basically, you could probably get the same result with (untested):
try:
    db = lite.connect('data.db')
except lite.DatabaseError:
    raise OSError('database file corrupt or not found.')
try:
    with db:
        db.execute(sql, parms)
except lite.IntegrityError:
    raise ValueError('invalid data')
# You may still need the finally, depending on what the with statement does
in sqlite3 - you'd have to check the documentation.

Chris

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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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