- From: Eric Prud'hommeaux <eric@w3.org>
- Date: Mon, 10 Jan 2011 22:55:11 -0500
- To: Andy Seaborne <andy.seaborne@epimorphics.com>
- Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
* Eric Prud'hommeaux <eric@w3.org> [2011-01-04 22:43-0500] > * Andy Seaborne <andy.seaborne@epimorphics.com> [2011-01-04 13:01+0000] > > > > > > On 03/01/11 17:16, Eric Prud'hommeaux wrote: > > >+ > > >I like using BINDINGs in subselects for getting my head around (i.e. > > >debugging) aggregate queries as it puts the pre-aggregated result set > > >directly in my face. I use this for didactic and testing purposes: > > > http://swobjects.svn.sourceforge.net/viewvc/swobjects/branches/sparql11/tests/sparql11/groupBy-f-having-f.rq?revision=1264&view=markup > > > > More generally, inline data tables - i.e. the ability to put data > > into a query directly. There are some ways to this - > > BINDINGS+SubSELECT but also anywhere AS is used can be combined with > > UNION to produce inline data. The latter may be very verbose :-) > > true, this validates: > SELECT ?a (COUNT(?b) AS ?d) WHERE { > { BIND (1 AS ?a) BIND (2 AS ?b) BIND (3 AS ?c) } > UNION { BIND (4 AS ?a) BIND (5 AS ?b) BIND (6 AS ?c) } > } GROUP BY ?c > > > > A more consistent approach might be: > > > > TABLE ?a ?b ?c { (1 2 3) (4 5 6) } > > > > to put anywhere in graph pattern. > > > > (not a proposal for this version of the spec) Thanks for sticking a BindingsClause on ASK CONSTRUCT and DESCRIBE (I've updated yacker). <http://www.w3.org/mid/20110103171603.GB23618@w3.org> proposed some reasons why a BindingsClause on a subselect was useful for federation. I agree that the above "TABLE" syntax would work (though it would require special code when serializing subselects vs. top-level queries), but see that you're not proposing it either. To that end, I'd like SubSelects to have a BindingsClause: -SubSelect ::= SelectClause WhereClause SolutionModifier +SubSelect ::= SelectClause WhereClause SolutionModifier BindingsClause? I'd also like to move the opt-ness out of the BindingsClause production and into the productions that reference it, e.g. -Query ::= Prologue ( SelectQuery | ConstructQuery | DescribeQuery | AskQuery ) BindingsClause +Query ::= Prologue ( SelectQuery | ConstructQuery | DescribeQuery | AskQuery ) BindingsClause? -BindingsClause ::= ( 'BINDINGS' Var* '{' ( '(' BindingValue+ ')' | NIL )* '}' )? +BindingsClause ::= 'BINDINGS' Var* '{' ( '(' BindingValue+ ')' | NIL )* '}' This will make it easier for those who wish to extend the grammar to use the production, as in your TABLE example above: -GraphPatternNotTriples ::= GroupOrUnionGraphPattern | OptionalGraphPattern | MinusGraphPattern | GraphGraphPattern | ServiceGraphPattern | Filter | Bind +GraphPatternNotTriples ::= GroupOrUnionGraphPattern | OptionalGraphPattern | MinusGraphPattern | GraphGraphPattern | ServiceGraphPattern | Filter | Bind | BindingsClause (not a proposal, just an example) > Just for yucks, I tried: > GraphPatternNotTriples ::= GroupOrUnionGraphPattern > | OptionalGraphPattern > | MinusGraphPattern > | GraphGraphPattern > | ServiceGraphPattern > | Filter > | Bind > | "BINDINGS" Var* "{" ( "(" BindingValue+ ")" | NIL )* "}"¹ > > and got no reduce/reuse/recycle conflicts. > > http://www.w3.org/2005/01/yacker?name=SPARQL_11&replace=1&lang=perl#prod-SPARQL_11-GraphPatternNotTriples > > e.g. http://www.w3.org/2005/01/yacker/uploads/SPARQL_11?lang=perl&text=SELECT+%3Fa+%28COUNT%28%3Fb%29+AS+%3Fd%29+WHERE+{%0D%0A++BINDINGS+%3Fa+%3Fb+%3Fc+{+%281+2+3%29+%284+5+6%29+}%0D%0A}+GROUP+BY+%3Fc&action=validate+text#language > > ¹ This is the same as the current BindingsClause except that > the BindingsClause is all optional. > > > > Andy > > -- > -ericP -- -ericP
Received on Tuesday, 11 January 2011 03:55:48 UTC