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
