Re: WIP: hooking parser

2009/2/16 Sam Mason <sam(at)samason(dot)me(dot)uk>:
> On Mon, Feb 16, 2009 at 02:35:54PM +0100, Pavel Stehule wrote:
>> attachment contains module that transform every empty string to null.
>
> Why would anyone ever want to do this? This would appear to break all
> sorts of things in very non-obvious ways:

I agree, so this behave is strange - but Oracle does it.

so normal query in Oracle for empty value looks like

select * from people where surname is null;

and some application expect transformation from '' to null.

http://www.thunderguy.com/semicolon/2003/04/26/oracle-empty-string-null/

so these modules (decode, oraemptystr) decrease differences between
PostgreSQL and Oracle.

Regards
Pavel Stehule

p.s. I am not Oracle expert, I expect so here are more qualified men.

>
> SELECT CASE s WHEN '' THEN 'empty string' ELSE s END FROM foo;
> UPDATE foo SET s = NULL WHERE s = '';
>
> would no longer do the expected thing. It would only do the expected
> thing (in my eyes) when strings of zero length were actually being
> inserted into the database. Like:
>
> INSERT INTO foo (s) VALUES ('');
> UPDATE foo SET s = '' WHERE s = 'empty string';
>
> Or am I missing something obvious?
>
> --
> Sam http://samason.me.uk/
>
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