IRC log of sparql on 2010-03-09

Timestamps are in UTC.

14:50:26 [RRSAgent]
RRSAgent has joined #sparql
14:50:26 [RRSAgent]
logging to
14:50:28 [trackbot]
RRSAgent, make logs world
14:50:28 [Zakim]
Zakim has joined #sparql
14:50:30 [trackbot]
Zakim, this will be 77277
14:50:30 [Zakim]
ok, trackbot; I see SW_(SPARQL)10:00AM scheduled to start in 10 minutes
14:50:31 [LeeF]
zakim, this will be SPARQL
14:50:31 [trackbot]
Meeting: SPARQL Working Group Teleconference
14:50:31 [trackbot]
Date: 09 March 2010
14:50:32 [Zakim]
ok, LeeF; I see SW_(SPARQL)10:00AM scheduled to start in 10 minutes
14:50:33 [LeeF]
Chair: LeeF
14:50:38 [LeeF]
Scribe: Souri
14:50:44 [LeeF]
14:53:11 [AlexPassant]
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14:55:36 [Zakim]
SW_(SPARQL)10:00AM has now started
14:55:42 [Zakim]
14:55:47 [AndyS]
zakim, ??P0 is me
14:55:47 [Zakim]
+AndyS; got it
14:57:08 [MattPerry]
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14:58:17 [bglimm]
bglimm has joined #sparql
14:58:26 [Zakim]
14:59:15 [Zakim]
14:59:23 [kasei]
Zakim, mute me
14:59:23 [Zakim]
kasei should now be muted
15:00:09 [ivan]
zakim, dial ivan-voip
15:00:09 [Zakim]
ok, ivan; the call is being made
15:00:11 [Zakim]
15:00:30 [tommik]
tommik has joined #sparql
15:00:34 [Zakim]
15:00:42 [bglimm]
Zakim, mute me
15:00:42 [Zakim]
bglimm should now be muted
15:01:09 [Zakim]
+ +035840564aaaa
15:01:19 [tommik]
zakim, aaaa is me
15:01:19 [Zakim]
+tommik; got it
15:01:26 [Zakim]
15:01:40 [LeeF]
zakim, who's on the phone?
15:01:40 [Zakim]
On the phone I see AndyS, MattPerry, kasei (muted), Ivan, bglimm (muted), tommik, LeeF
15:01:59 [AndyS]
Hi all.
15:02:17 [Zakim]
15:02:21 [AlexPassant]
Zakim, ??P19 is me
15:02:21 [Zakim]
+AlexPassant; got it
15:02:34 [AxelPolleres]
AxelPolleres has joined #sparql
15:02:38 [LeeF]
Scribe: MattPerry
15:02:41 [LeeF]
Scribenick: MattPerry
15:02:46 [LeeF]
Regrets+ Souri
15:03:01 [Zakim]
15:03:18 [LeeF]
PROPOSED: Approve minutes at
15:03:59 [LeeF]
RESOLVED: Approve minutes at
15:04:23 [SteveH]
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15:04:32 [SteveH]
hi all
15:04:34 [LeeF]
Next meeting: 2010-03-16 @ 14:00 UK / 10:00 EDT
15:05:04 [ivan]
possible regrets for me
15:05:26 [MattPerry]
LeeF: 2 weeks of 4 hr difference
15:05:31 [Zakim]
+ +0207735aabb
15:05:43 [SteveH]
Zakim, aabb is me
15:05:43 [Zakim]
+SteveH; got it
15:06:49 [MattPerry]
LeeF: may be a problem that Paul is not here ... but we will try to make decisions anyway
15:07:13 [LeeF]
15:07:27 [MattPerry]
Topic: Blank Nodes in Delete
15:08:01 [MattPerry]
Option 1: no blank nodes in delete template
15:08:16 [MattPerry]
Option 2: blank nodes as wildcard in delete template
15:09:56 [MattPerry]
LeeF: if prohibit blank nodes now can we change it later
15:10:16 [Zakim]
15:10:47 [bglimm]
Zakim, unmute me
15:10:47 [Zakim]
bglimm should no longer be muted
15:11:09 [AndyS]
I don't understand why if we exclude bnode syntax now we are effectively deciding for the future.
15:11:22 [LeeF]
AndyS, yes, that's what I was trying to say
15:11:28 [MattPerry]
bglimm: can live with no blank nodes but would be better with them
15:11:31 [ivan]
15:11:37 [LeeF]
ack ivan
15:12:26 [SteveH]
15:12:31 [bglimm]
q+ to ask about deleting lists without allowing bnodes
15:12:33 [LeeF]
ack SteveH
15:12:34 [MattPerry]
ivan: there are non-entailment related use cases that need blank nodes
15:13:30 [LeeF]
DELETE { ?x :hasList (1 2 3) } WHERE { ... ?x }
15:13:35 [AxelPolleres]
(just to be able to follow... what is discussed - said by ivan - is that not allowing to "delete bnodes" would not allow to delete lists?
15:14:24 [LeeF]
ack bglimm
15:14:24 [Zakim]
bglimm, you wanted to ask about deleting lists without allowing bnodes
15:14:45 [MattPerry]
SteveH: rdf list blank node shortcut doesn't add new functionality just makes it easier
15:14:48 [ivan]
15:14:50 [bglimm]
ack bglimm
15:14:58 [AxelPolleres]
what does this mean if the data graph has two lists (1 2 3) as value of :hasList ? (with different bnode ids?)
15:15:41 [AxelPolleres]
15:16:08 [ivan]
ack ivan
15:16:15 [AxelPolleres]
q+ to ask whether the vars in the DELETE template don't need to be bound in the WHERE
15:16:36 [LeeF]
ack ivan
15:16:41 [SteveH]
15:17:16 [AxelPolleres]
ack axel
15:17:16 [Zakim]
AxelPolleres, you wanted to ask whether the vars in the DELETE template don't need to be bound in the WHERE
15:17:17 [LeeF]
ack AxelPolleres
15:17:50 [LeeF]
ack SteveH
15:17:59 [MattPerry]
LeeF: long var-based list expression must be repeated in both Delete and Where
15:18:40 [MattPerry]
SteveH: can you use property paths to get list variables?
15:18:48 [AxelPolleres]
so, just to note, such a delete would indeed all the matching lists (answering my own question from further above)
15:19:37 [LeeF]
straw poll: preference between (1) prohibiting blank nodes in DELETE templates and (2) blank nodes in DELETE templates act as wild cards
15:19:44 [ivan]
15:19:54 [AndyS]
Wheer are we on need "all triples must match" rule -- else chaos may result (half a list goes if wrong length)
15:19:55 [LeeF]
ack ivan
15:20:12 [MattPerry]
ivan: also same blank node cannot be in both delete and where
15:20:15 [kasei]
15:20:18 [AndyS]
Pref: 2
15:20:20 [bglimm]
15:20:23 [kasei]
Zakim, unmute me
15:20:23 [Zakim]
kasei should no longer be muted
15:20:23 [ivan]
Pref: 2
15:20:25 [LeeF]
ack kasei
15:20:32 [SteveH]
pref: 1, but 2 probably ok
15:20:37 [MattPerry]
Pref: 2
15:21:13 [ivan]
15:21:17 [MattPerry]
kasei: can rdf list be a special case?
15:21:23 [AxelPolleres]
slight pref 2, still don't feel sure about implications
15:21:55 [MattPerry]
kasei: grammar can enforce this
15:22:11 [LeeF]
ack ivan
15:22:13 [MattPerry]
LeeF: specification still needs to give semantics for blank nodes
15:22:25 [kasei]
Zakim, mute me
15:22:25 [Zakim]
kasei should now be muted
15:22:38 [LeeF]
My preference is for #1
15:22:50 [MattPerry]
ivan: many cases for blank nodes beyond rdf lists
15:23:00 [AxelPolleres]
q+ to note that conceptually, it seems strange, since it would be the only place where bnodes have a "universal variables" meaning, whereas anywhere alse they rather indicate "existential variables"
15:23:19 [AxelPolleres]
... but I have no better proposal
15:23:27 [LeeF]
ack AxelPolleres
15:23:27 [Zakim]
AxelPolleres, you wanted to note that conceptually, it seems strange, since it would be the only place where bnodes have a "universal variables" meaning, whereas anywhere alse they
15:23:27 [AndyS]
but they are bnodes in the data. a ?var can be bound to a data bnode
15:23:31 [Zakim]
... rather indicate "existential variables"
15:24:00 [bglimm]
I think in my examples you could always use the [] notation and as I understand it, that would be allowd even under 1
15:24:42 [bglimm]
and Steve
15:25:06 [AndyS]
opt 1 bans [] in delete template AIUI
15:25:07 [SteveH]
I'm about -0.5
15:25:30 [LeeF]
PROPOSED: Blank nodes in DELETE templates act as "wild cards", effectively as variables bound to all RDF terms; the same blank node cannot be used in the WHERE clause and the template, or in multiple BGPs
15:26:03 [kasei]
15:26:05 [ivan]
second it
15:26:06 [bglimm]
15:26:07 [ivan]
15:26:16 [SteveH]
15:26:20 [dcharbon2]
15:26:42 [LeeF]
RESOLVED: Blank nodes in DELETE templates act as "wild cards", effectively as variables bound to all RDF terms; the same blank node cannot be used in the WHERE clause and the template, or in multiple BGPs, SteveH, dcharbon2, LeeF abstaining
15:26:50 [AxelPolleres]
+1 (lacking better solutions)
15:27:28 [LeeF]
15:27:28 [MattPerry]
Topic: Data Sets in SPARQL Update
15:27:40 [SteveH]
15:27:41 [SteveH]
something like:
15:27:43 [SteveH]
DELETE { ?n rdf:first ?f ; rdf:rest ?n }
15:27:43 [SteveH]
WHERE { <list> rdf:first*/rdf:rest* ?n . ?n rdf:first ?f ; rdf:next ?n }
15:27:44 [SteveH]
15:30:07 [MattPerry]
LeeF: SPARQL query allows specification of an RDF Dataset, but SPARQL update does not allow query to select specific RDF Dataset
15:30:33 [SteveH]
15:30:49 [AndyS]
Is this different from using GRAPH in the pattern?
15:31:00 [SteveH]
GRAPH ?g ... FILTER(?g = <a> || ...)
15:31:24 [MattPerry]
LeeF: what is the scope of graphs that the WHERE is matched against?
15:31:35 [AndyS]
If the default dataset is changed (to some union using FROM...), it goes make a difference.
15:32:19 [MattPerry]
LeeF: No way to give default graph for update
15:32:28 [AndyS]
q+ to ask how does this interact with WITH?
15:32:30 [LeeF]
15:32:33 [LeeF]
ack SteveH
15:33:02 [ivan]
Lees' syntax example: INSERT INTO <g1> { template } FROM g2 FROM g3 FROM NAMED g4 FROM NAMED
15:33:02 [ivan]
g5 WHERE { GRAPH ?g { ?s ?p ?o } }
15:33:10 [LeeF]
SELECT ... FROM <g1> FROM <g2> { tp1 . tp2 }
15:33:51 [LeeF]
SELECT ... { GRAPH ?g1 { tp1 } . GRAPH ?g2 { tp2 } }
15:34:16 [MattPerry]
LeeF: can do this with GRAPH but WHERE gets very complicated
15:34:17 [AndyS]
not quite - tp may span g1 and g2.
15:34:34 [LeeF]
AndyS, one tp can span two graphs?
15:34:37 [LeeF]
15:34:39 [LeeF]
ack AndyS
15:34:39 [Zakim]
AndyS, you wanted to ask how does this interact with WITH?
15:34:57 [AxelPolleres]
SELECT ... { GRAPH ?g1 { tp1 } . GRAPH ?g2 { tp2 } } FILTER (?g1 = <g1> or ?g1= <g2> and ?g2 = <g1> or ?g2= <g2> )
15:34:59 [AxelPolleres]
15:35:36 [LeeF]
AxelPolleres, right
15:35:37 [AndyS]
tp1 can match g1 or g2, tp2 can match g1 or g2 => 4 cases
15:35:37 [LeeF]
15:35:50 [AndyS]
(bnodes ... :-))
15:36:12 [AxelPolleres]
15:36:22 [AndyS]
I'm happy to consider the design. Seems harmless (so far).
15:36:54 [AndyS]
I can see that WITH != FROM (WITH is the updated graph, FROM is the queried graph)
15:37:08 [LeeF]
ack AxelPolleres
15:38:12 [AndyS]
Can't update a synthetic graph (e.g. merge of 2 graphs)
15:38:27 [LeeF]
15:38:39 [AndyS]
LeeF, your suggestion is good.
15:39:01 [MattPerry]
LeeF: interaction of WITH and FROM needs more investigation
15:39:16 [AxelPolleres]
I see a problem with e.g. INSERT { ?X p ?Y } FROM <g1> FROM <g2> WHERE { ?X p1 o1 . ?Y p2 o2. }
15:40:31 [AxelPolleres]
... don't know what it means. A proposal should make this corner cases clear, before we can really figure out whether/where it is useful.
15:41:09 [LeeF]
ACTION: Lee to work with Paul to flesh out design proposal for FROM/FROM NAMED (datasets) in SPARQL Update
15:41:09 [trackbot]
Created ACTION-202 - Work with Paul to flesh out design proposal for FROM/FROM NAMED (datasets) in SPARQL Update [on Lee Feigenbaum - due 2010-03-16].
15:41:45 [LeeF]
15:42:00 [MattPerry]
Topic: Update Fault Types
15:42:55 [MattPerry]
AndyS: with HTTP there are few error codes
15:44:03 [MattPerry]
dcharbon2: WSDL 2.0 has no limit on error codes
15:44:06 [dcharbon2]
15:45:41 [Zakim]
15:45:43 [SteveH]
15:46:09 [LeeF]
ACK SteveH
15:49:07 [Zakim]
15:49:08 [AlexPassant]
Zakim, ??P2 is me
15:49:08 [Zakim]
+AlexPassant; got it
15:49:22 [MattPerry]
LeeF: does it make sense to have a lot of faults if there are only a couple of error codes?
15:50:29 [MattPerry]
dcharbon2: could start with 2 basic error codes and see what users think
15:50:30 [kasei]
i'd be interested in seeing the use of many of the 2xx http codes be conformant (going beyond the idea of just faults). 202 in particular.
15:51:23 [MattPerry]
LeeF: what code does drop non-existent graph map to?
15:51:26 [kasei]
400 bad request seems like a potential status code...
15:51:56 [AndyS]
"202 Accepted" is not an error? 2xx are all positives? Text is "Successful 2xx"
15:52:06 [AndyS]
?? "304 Not Modified"
15:52:13 [SteveH]
could be
15:52:20 [MattPerry]
SteveH: there are many more-specific HTTP codes to use
15:53:10 [MattPerry]
LeeF: lets hold off on error codes until update language is set
15:54:02 [MattPerry]
AndyS: it is still useful to identify what the possible errors are even though they are not exposed in the SPARQL protocol
15:54:14 [SteveH]
+1 to AndyS
15:54:21 [MattPerry]
AndyS: informative text can do this
15:55:35 [MattPerry]
LeeF: Next week HTTP protocol, Property Paths, what is and is not in update language, and F2F
15:55:49 [Zakim]
15:55:50 [Zakim]
15:55:50 [Zakim]
15:55:50 [Zakim]
15:55:53 [Zakim]
15:55:54 [Zakim]
15:55:56 [Zakim]
15:55:56 [ivan]
zakim, drop me
15:55:56 [Zakim]
Ivan is being disconnected
15:55:58 [Zakim]
15:55:58 [Zakim]
15:56:12 [SteveH]
it's spooky that zakim knows more of my phone umber than I do :)
15:56:20 [AndyS]
zakim, drop me
15:56:20 [Zakim]
AndyS is being disconnected
15:56:22 [Zakim]
15:58:52 [kasei]
can anyone help me parse a sentence from the RDF/XML spec?
15:59:13 [LeeF]
kasei, can try :D
15:59:25 [kasei]
i'm looking for a URI that identifies RDF/XML, the serialization format.
15:59:33 [kasei]
section 5.1 says, "The RDF Vocabulary is identified by this namespace name"
15:59:42 [kasei]
I'm trying to sort out if "RDF Vocabulary" is what I'm after.
15:59:51 [kasei]
I suspect not, but not totally sure.
15:59:56 [AndyS]
no, it's not.
16:00:10 [AndyS]
RDF vocab is "rdf:type" etc.
16:00:23 [kasei]
bah. annoyed that we've been able to get this far without URIs for some very basic stuff!
16:00:32 [AndyS]
Not sure there is a URI for the synatx - is there a URI for every MIME type?
16:01:09 [AndyS]
There is naming competition between MIME types and formats ... so not sure if anyone has been bold enough to go there.
16:01:10 [kasei]
well, much like the rdf/xml spec, there's probably an offical information resource for mime types, but that's different.
16:01:27 [AndyS]
Fairly certain W3C hasn't - would be a nice suprise if they had.
16:01:30 [AndyS]
16:02:13 [kasei]
wonder if this is the sort of thing that might be added to rdf/xml based on the upcoming workshop...
16:02:43 [AndyS]
kasei, Graham Klyne would be a good person to ask - he tracks IETF and W3C.
16:02:50 [kasei]
if we go ahead with this saddle:resultFormat stuff in the SDs, I'd like to be able to point to URIs for the standard formats.
16:03:06 [SteveH]
kasei, didn't saddle: use mime types?
16:03:31 [kasei]
it used both mime types and a link to the spec's webpage.
16:03:37 [SteveH]
16:03:47 [SteveH]
given that conneg works on mime types, that's not a bad idea
16:03:53 [kasei]
which is fine if you don't have a proper URI, I suppose, but I think we can/should do better.
16:05:19 [kasei]
also, with the confusion around some mime types for rdf, I'd rather not lean too heavily on them as identifiers.
16:05:47 [SteveH]
16:06:23 [Zakim]
16:06:23 [kasei]
especially n-triples. text/plain isn't exactly the most useful thing for conneg.
16:06:24 [Zakim]
SW_(SPARQL)10:00AM has ended
16:06:25 [Zakim]
Attendees were AndyS, MattPerry, kasei, Ivan, bglimm, +035840564aaaa, tommik, LeeF, AlexPassant, dcharbon2, +0207735aabb, SteveH, AxelPolleres
16:09:21 [AndyS]
agree re text/plain. They didn't plan to let it out of the WG as a format - but it escaped. Feral format.
16:09:40 [kasei]
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