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Re: try pattern for database connection with the close method

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On 21/02/2015 02:42, Mario Figueiredo wrote:
> Hello all,
>
> I'm using the following pattern for db access  that requires me to
> close the connection as soon as it is not needed:
>
>          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()
>
> Since it's a bit verbose, is there a better way?
>
> Note: The user of this API has the whole database functionality
> abstracted away. Hence the exception channeling in the except clauses.
>

Use your context manager at the outer level.

import sqlite3 as lite

try:
     with lite.connect('data.db') as db:
     try:
         db.execute(sql, parms)
     except lite.IntegrityError:
         raise ValueError('invalid data')
except lite.DatabaseError:
     raise OSError('database file corrupt or not found.')

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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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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