Re: #escape_string_warning = off

Dennis Björklund <db@zigo.dhs.org>

From: Dennis Bjorklund <db@zigo.dhs.org>
To: Jeff Davis <jdavis-pgsql@empires.org>
Cc: Marko Kreen <marko@l-t.ee>, "Joshua D. Drake" <jd@commandprompt.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2005-08-02T08:35:17Z
Lists: pgsql-hackers
On Tue, 2 Aug 2005, Jeff Davis wrote:

> >>Does the SQL standard provide no way to have a NULL character in a
> >>string constant? Is single-quote the only special character?
> > 
> > I don't think it forbids you from using the null character. It's not like 
> > the strings are zero terminated. Some encodings might not allow the null 
> > character, but that's different.
> 
> But doesn't PostgreSQL forbid us from using the NULL character in a
> query at all? Don't we always have to escape or encode it in some way?

Pg does not allow \0 in strings at all. Try SELECT 'abc\0def'; in the
current version of pg.

The sql standard doesn't forbid null values in strings as far as I know
and that's all I talked about. To have a sql standard string with null
inside you just insert the 0 byte (for normal single byte encodings), no
escaping needed.

Internally pg handles strings as \0-terminated entities which is a bit 
unfortunate but that's what we have. That's why 'abc\0def' became the 
string 'abc'. Most character sets forbid \0 in strings anyway.

-- 
/Dennis Björklund