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Re: DELETE and blank nodes

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Wed, 03 Mar 2010 15:34:49 +0000
Message-ID: <4B8E8199.4050704@talis.com>
To: Lee Feigenbaum <lee@thefigtrees.net>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>


On 03/03/2010 6:16 AM, Lee Feigenbaum wrote:
> == The Proposals ==
>
> I see only two realistic proposals emerging from this.
>
> 1/ We prohibit blank nodes in the DELETE template completely.

This is just to bring out consequences I can see of the possibilities:

Minor: this can be done with another set of parser rules for a 
"DeleteTemplate" or a textual prohibition when using the same quads 
template form for INSERT.

We already have a template form of only ground data for INSERT|DELETE 
DATA using quads; the template for CONSTRUCT, the template for INSERT 
(again, we may wish to define it's semantics to insert all triples if 
all are legal, unlike CONSTRUCT).

For yet another template hierarchy: all the rules are part of the 
published grammar.

Against: grammar gets larger (but it's already sufficiently large)

(BNF does not support grammar structural sharing :-()

> 2/ Blank nodes in DELETE templates act as "wild cards"--effectively
> variables pre-bound to all RDF terms--to let us write some shortcuts and
> handle Sandro's case of deleting RDF lists. We prohibit the same blank
> node label from being used in multiple scopes.

	Andy
Received on Wednesday, 3 March 2010 15:35:21 GMT

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