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Re: Keeping python code and database in sync

References <mailman.13604.1409316126.18130.python-list@python.org> <roy-AE646E.10535529082014@news.panix.com> <CANc-5UxEY4XgmoiNa5MR=1Hy8SeRtpr1r=rRjBFKw2RrxFNomQ@mail.gmail.com>
Date 2014-08-30 08:31 +1000
Subject Re: Keeping python code and database in sync
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.13622.1409351518.18130.python-list@python.org> (permalink)

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On Sat, Aug 30, 2014 at 3:04 AM, Skip Montanaro <skip@pobox.com> wrote:
> On Fri, Aug 29, 2014 at 9:54 AM, Roy Smith <roy@panix.com> wrote:
>> Yeah, schema migration is an ugly problem.
>
> It's not really any worse than any other sort of complex data
> structure change, is it? If your persistent data lived in a pickle
> file, it would likely be as bad or worse.

Well, correct. The problem isn't because it's in a database; the
problem is a consequence of persistent structured data that can get
out of sync.

It's easy to solve in a simple way that breaks on any sort of
confusion. It takes a bit more complexity (like the scheme I
suggested) to handle a few more cases. It takes a lot more complexity
(like the migration tools Roy listed) to cope with lots of awkward
cases (I suspect at least some of them will handle back-levelling,
which my scheme doesn't). And I doubt any of them is absolutely
perfect.

>> ... suckitude ...
>
> Nice word. Let's use it more so my polly app will see it as a common
> word and maybe offer it to me in a potential XKCD 936 password. :-)
>
> suckitude suckitude suckitude suckitude suckitude suckitude suckitude
>

Yeah, it's a great word. As a general rule, suckitude increases with
the square of design complexity and superlinearly with number of bugs.
I'm not sure how suckitude is affected by bugs, exactly; possibly O(N
log N), because each bug has a small probability of affecting another
bug.

ChrisA

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Thread

Keeping python code and database in sync "Frank Millman" <frank@chagford.com> - 2014-08-29 14:42 +0200
  Re: Keeping python code and database in sync Rustom Mody <rustompmody@gmail.com> - 2014-08-29 05:55 -0700
    Re: Keeping python code and database in sync "Frank Millman" <frank@chagford.com> - 2014-08-29 15:19 +0200
  Re: Keeping python code and database in sync Roy Smith <roy@panix.com> - 2014-08-29 10:54 -0400
    Re: Keeping python code and database in sync Skip Montanaro <skip@pobox.com> - 2014-08-29 12:04 -0500
    suckitude classifications [was Re: Keeping python code and database in sync] Ethan Furman <ethan@stoneleaf.us> - 2014-08-29 12:02 -0700
    Re: Keeping python code and database in sync Ben Finney <ben+python@benfinney.id.au> - 2014-08-30 06:34 +1000
    Re: Keeping python code and database in sync Chris Angelico <rosuav@gmail.com> - 2014-08-30 08:31 +1000
    Re: suckitude classifications [was Re: Keeping python code and database in sync] Chris Angelico <rosuav@gmail.com> - 2014-08-30 08:38 +1000
      Re: suckitude classifications [was Re: Keeping python code and database in sync] Roy Smith <roy@panix.com> - 2014-08-29 19:19 -0400
        Re: suckitude classifications [was Re: Keeping python code and database in sync] Chris Angelico <rosuav@gmail.com> - 2014-08-30 09:38 +1000
    Re: Keeping python code and database in sync Skip Montanaro <skip.montanaro@gmail.com> - 2014-08-29 18:47 -0500
    Re: Keeping python code and database in sync Ethan Furman <ethan@stoneleaf.us> - 2014-08-29 16:54 -0700
    Re: Keeping python code and database in sync Skip Montanaro <skip@pobox.com> - 2014-08-29 21:14 -0500
    Re: Keeping python code and database in sync Chris Angelico <rosuav@gmail.com> - 2014-08-30 12:28 +1000
    Re: suckitude classifications {taken to absurdity} Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-08-30 11:13 -0400

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