Re: Searching for lots of similar strings (filenames) in sqlite3 database

Path	csiph.com!usenet.pasdenom.info!aioe.org!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From	Adam Funk <a24061@ducksburg.com>
Newsgroups	comp.lang.python
Subject	Re: Searching for lots of similar strings (filenames) in sqlite3 database
Date	Wed, 02 Jul 2014 13:30:08 +0100
Organization	$CABAL
Lines	34
Message-ID	<gjad8bxpvp.ln2@news.ducksburg.com> (permalink)
References	<tgia8bx2sf.ln2@news.ducksburg.com> <mailman.11362.1404216365.18130.python-list@python.org> <3uva8bx3dn.ln2@news.ducksburg.com> <mailman.11375.1404230249.18130.python-list@python.org> <770d8bxunj.ln2@news.ducksburg.com> <mailman.11407.1404295399.18130.python-list@python.org>
Injection-Info	mx05.eternal-september.org; posting-host="11f0a8c60cd96a09a54ba99a860a92e6"; logging-data="25609"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18mXVXFMhOxcX3dZcfYL1KVkADasIQgqS4="
User-Agent	slrn/pre1.0.2-9 (Linux)
Cancel-Lock	sha1:NoupTZjFXJdu+CbKlqjdMdZMmYE= sha1:8zt2y7Ku51vg8ckGK9uLyNPR4Ks=
Xref	csiph.com comp.lang.python:73837

Show key headers only | View raw

On 2014-07-02, Chris Angelico wrote:

> On Wed, Jul 2, 2014 at 7:32 PM, Adam Funk <a24061@ducksburg.com> wrote:
>> Well, I've changed it to the following anyway.
>>
>>         subdir_glob = subdir + '/*'
>>         cursor.execute('SELECT filename FROM files WHERE filename GLOB ?',
>>                        (subdir_glob,))
>>         rows = cursor.fetchall()
>>         known_files = {row[0] for row in rows}
>>
>> I see what you mean about paths containing '%', but I don't see why
>> you were concerned about underscores, though.
>
> With GLOB, presumably ? matches a single character and * matches any
> number of characters. With LIKE, _ matches a single character and %
> matches any number. So, for instance, WHERE filename LIKE
> '/foo/bar/spam_spam/%' will match '/foo/bar/spam2spam/1234', which may
> be a little surprising. It's not going to be a serious problem in most
> cases, as it'll also match '/foo/bar/spam_spam/1234', but the false
> positives will make one of those "Huhhhhh????" moments if you don't
> keep an eye on your magic characters.
>
> In your specific case, you happen to be safe, but as I look over the
> code, my paranoia kicks in and tells me to check :) It's just one of
> those things that flags itself to the mind - anything that might help
> catch bugs early is a good feature of the mind, in my opinion!

Oh, I'd just missed the '_' in the LIKE documentation.  Doh!


-- 
Indentation is for enemy skulls, not code!
            --- Klingon Programmer's Guide

Thread

Searching for lots of similar strings (filenames) in sqlite3 database Adam Funk <a24061@ducksburg.com> - 2014-07-01 12:26 +0100
  Re: Searching for lots of similar strings (filenames) in sqlite3 database Chris Angelico <rosuav@gmail.com> - 2014-07-01 22:06 +1000
    Re: Searching for lots of similar strings (filenames) in sqlite3 database Adam Funk <a24061@ducksburg.com> - 2014-07-01 16:15 +0100
      Re: Searching for lots of similar strings (filenames) in sqlite3 database Chris Angelico <rosuav@gmail.com> - 2014-07-02 01:57 +1000
        Re: Searching for lots of similar strings (filenames) in sqlite3 database Adam Funk <a24061@ducksburg.com> - 2014-07-02 10:30 +0100
        Re: Searching for lots of similar strings (filenames) in sqlite3 database Adam Funk <a24061@ducksburg.com> - 2014-07-02 10:32 +0100
          Re: Searching for lots of similar strings (filenames) in sqlite3 database Chris Angelico <rosuav@gmail.com> - 2014-07-02 20:03 +1000
            Re: Searching for lots of similar strings (filenames) in sqlite3 database Adam Funk <a24061@ducksburg.com> - 2014-07-02 13:30 +0100
  Re: Searching for lots of similar strings (filenames) in sqlite3 database MRAB <python@mrabarnett.plus.com> - 2014-07-01 13:13 +0100
  Re: Searching for lots of similar strings (filenames) in sqlite3 database Chris Angelico <rosuav@gmail.com> - 2014-07-02 00:02 +1000

csiph-web