Обсуждение: [PATCH] Documentation: remove confusing paragraph about backslash escaping

Hi!

As with recent changes to `standard_conforming_strings' the paragraph
about backslash escaping in the description of `LIKE' is only confusing.
Thus I attached a patch to remove it.

Greetings,

   Hannes

--
Hannes Sowa                   <hsowa@bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99

On Mon, Feb 27, 2012 at 10:17 AM, Hannes Frederic Sowa <hsowa@bfk.de> wrote:
> As with recent changes to `standard_conforming_strings' the paragraph about
> backslash escaping in the description of `LIKE' is only confusing. Thus I
> attached a patch to remove it.

I think I agree with removing this paragraph; it made sense when
standard_conforming_strings=off was the default, but that's not so
anymore.  We could come up with some alternative text to insert here
but I think that might be unnecessarily long-winded.

Other opinions?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Hannes Frederic Sowa <hsowa@bfk.de> writes:
> As with recent changes to `standard_conforming_strings' the paragraph 
> about backslash escaping in the description of `LIKE' is only confusing. 
> Thus I attached a patch to remove it.

The para is still relevant if you don't have standard_conforming_strings
on.  It could probably use work but I don't think simply removing it
is appropriate.
        regards, tom lane

* Tom Lane:

> Hannes Frederic Sowa <hsowa@bfk.de> writes:
>> As with recent changes to `standard_conforming_strings' the paragraph
>> about backslash escaping in the description of `LIKE' is only confusing.
>> Thus I attached a patch to remove it.
>
> The para is still relevant if you don't have standard_conforming_strings
> on.

And if you aren't using parametrized queries.  The old text is a bit
misleading even with standard_conforming_strings set to off.  It is
technically correct because it refers to the SQL statement parser which
is run on parameters, but this seems a pretty fine distinction.

--
Florian Weimer                <fweimer@bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99

Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Feb 27, 2012 at 10:17 AM, Hannes Frederic Sowa <hsowa@bfk.de> wrote:
>> As with recent changes to `standard_conforming_strings' the paragraph about
>> backslash escaping in the description of `LIKE' is only confusing. Thus I
>> attached a patch to remove it.

> I think I agree with removing this paragraph; it made sense when
> standard_conforming_strings=off was the default, but that's not so
> anymore.  We could come up with some alternative text to insert here
> but I think that might be unnecessarily long-winded.

On a closer look, I see three different places in the
functions-matching.html page that talk about doubling backslashes, of
which this one might be the least bogus, since it at least provides
a cross-reference to someplace where you would read about
standard_conforming_strings.

I suggest replacing the first and third cases with something along the
lines of
Note: if you have standard_conforming_strings turned off, anybackslashes you write in literal string constants will
needto bedoubled.  See Section 4.1.2.1 for more information.
 

The second case is just a parenthetical comment and perhaps could be
removed.
        regards, tom lane

On 02/28/2012 12:10 AM, Tom Lane wrote:
> I suggest replacing the first and third cases with something along the
> lines of
>
>     Note: if you have standard_conforming_strings turned off, any
>     backslashes you write in literal string constants will need to be
>     doubled.  See Section 4.1.2.1 for more information.
>
> The second case is just a parenthetical comment and perhaps could be
> removed.

Definitely OK by me. Thanks for looking into this!

-- 
Hannes Sowa                   <hsowa@bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99