Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #26135

Re: Generating valid identifiers

Date 2012-07-27 09:28 +0200
From Laszlo Nagy <gandalf@shopzeus.com>
Subject Re: Generating valid identifiers
References <mailman.2604.1343305588.4697.python-list@python.org> <50116281$0$29978$c3e8da3$5496439d@news.astraweb.com> <CALwzidnR-H=VCWAiC-qL95C_8C_A=+LMWvCAq4+0ZCM2-UHbVw@mail.gmail.com> <CALwzidmFmXGRQbSNjC4V6maCoTzvW8aP4-zfMWiu1aV_ihocjQ@mail.gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.2649.1343374141.4697.python-list@python.org> (permalink)

Show all headers | View raw

> As a side note, the odds of having at least one hash collision among
> multiple tables are known as the birthday problem.  At 4 hex digits
> there are 65536 possible digests, and it turns out that at 302 tables
> there is a >50% chance that at least one pair of those names have the
> same 4-digit digest.  That doesn't mean you should be concerned if you
> have 302 tables in your Django Oracle database, though, because those
> colliding tables also have to match completely in the first 26
> characters of their generated names, which is not that common.  If a
> collision ever did occur, the resolution would be simple: manually set
> the name of one of the offending tables in the model definition.
>
> With 16 ** 10 possible digests, the probability of collision hits 50%
> at 1234605 tables.
Thank you for the precise explanation. :-) Well, if Django and Oracle 
uses this, then it can't be a very bad idea. :-)

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Generating valid identifiers Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-26 14:26 +0200
  Re: Generating valid identifiers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-26 15:30 +0000
    Re: Generating valid identifiers Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-26 20:08 +0200
    Re: Generating valid identifiers Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-26 13:28 -0600
      Re: Generating valid identifiers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-27 01:54 +0000
        Re: Generating valid identifiers Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-27 09:34 +0200
    Re: Generating valid identifiers Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-26 14:00 -0600
    Re: Generating valid identifiers Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-27 09:28 +0200
    Re: Generating valid identifiers Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-27 11:59 +0200

csiph-web