On 11-08-24 01:17 PM, Ashar Voultoiz wrote:
> Hello,
>
> During the Berlin hack-a-ton (which was an awesome event), I have added
> a quick hack to MediaWiki which is correctly marked as fixme. The
> revision I am requesting comments for is r87992:
>
> http://www.mediawiki.org/wiki/Special:Code/MediaWiki/87992
>
> Copy pasting the example from the commit message:
>
> Example:
> $db->makeList( array( 'field!' => array( 1,2,3 ) );
> outputs:
> 'field' NOT IN ('1', '2', '3' );
>
> $db->makeList( array( 'foo!' => array( 777 ) ) );
> outputs:
> 'foo' =! 777
>
>
> The exclamation mark is an easy mark to have the condition negated.
>
> Brion raised concerns: syntax is not obvious and lacking potentially
> useful feature. He recommends using full operators:
>
> 'some_field IS NOT' => null,
> 'some_value !=' => 23,
> 'some_ts >=' => $db->timestamp($cutoff),
> 'some_ts <' => $db->timestamp($cutoff),
>
> Thus the proposed diff is:
> - 'field!'
> + 'field !='
>
> I would appreciate if developers can comment on this feature, either on
> the mailing list or on the revision comment list.
>
>
> NB: please note the 'field!' feature has been used in the code since
> there. Might need to have to fix them if we change the code.
IMHO we are deeply in need of a way to abstract operators.
In various places in code we drop down to things like
'column_a>column_b' which is treated as raw sql.
The biggest problem is !=. The != operator is actually a MySQLism and
not valid standard SQL. The standard way to do this in SQL is with <>.
While some engines like PostgreSQL and Sqlite implement != in addition
to <> for compatibility with stuff written for MySQL, there are other DB
engines like CUBRID which rightfully consider != to be invalid and break.
Though the idea of supporting 'field op' is an interesting new take on
this idea, as long as we make sure that we explicitly say that it's only
the operator we support there, not raw sql just being dumped. So that we
have a way to support engines that use <>.
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]
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