- From: Dan Connolly <connolly@w3.org>
- Date: Wed, 02 Sep 2009 10:03:39 -0500
- To: "Seaborne, Andy" <andy.seaborne@hp.com>
- Cc: Lee Feigenbaum <lee@thefigtrees.net>, Chimezie Ogbuji <ogbujic@ccf.org>, "public-sparql-dev@w3.org" <public-sparql-dev@w3.org>
On Wed, 2009-09-02 at 09:31 +0000, Seaborne, Andy wrote:
[...]
>
> One possibility the working group is considering is NOT EXISTS (also known as UNSAID)
>
> PREFIX : <http://example/>
>
> SELECT *
> {
> ?x a ?t
> NOT EXISTS { ?x a :C }
> }
>
> -----------
> | x | t |
> ===========
> | :b | :D |
> -----------
>
> Which I think is easier to read.
The irony is kinda thick... we looked at UNSAID
in Jan 2005 too...
http://www.w3.org/2001/sw/DataAccess/ftf4.html#item04
The arguments for BOUND over UNSAID included
"users were less likely to write difficult-to-optimize queries
with UNSAID."
well, yeah... users are less likely to use mystifying features. ;-)
The next argument was:
"BOUND seemed easier to teach and learn to several WG members,
as well."
That seemed counter-intuitive to me at the time, but there
wasn't much to go on at the time.
Since then, if experience has shown me/us anything, it's that
BOUND is _not_ easy to teach and learn.
--
Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541 0875 0F91 96DE 6E52 C29E
Received on Wednesday, 2 September 2009 15:03:50 UTC