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ok
<scribe> scribe: bertails
<scribe> scribenick: betehess
PROPOSAL: approving the mminutes
+1
<soeren> +1
RESOLUTION: minutes are approved
<ericP> ivan and i will be there in a moment
Ashok: juansequeda you requested
to speak about @something@
... I'd like you to speak about the DM spec
... then we can speak about '#' and '=' stuff
... last time we spoke about publishing the spec
... the DM guys were a bit hesitant
... as they prefer to publish when they think they are
ready
juansequeda: we said to publish
in *two* weeks
... that was my issue
Souri: I'll be on vacation in one month
juansequeda: I'll leave for Chile
on Friday
... we'll work with Marcelo
... I'd like to speak the many-to-many with richard
<Zakim> MacTed, you wanted to discuss provenance
MacTed: that may be dangerous
thing
... I haven't had time to write that earlier
... wanted to speak about that several weeks ago
... about temporality issue
... ericP was operating under the assumption that things are
static forever
... and other people too
... so there has to be a provenance associated with
everything
... "this stuff is right at that moment"
Ashok: your
recommendations?
... you want the mapping having a timestamp?
MacTed: not necessaraly
... if we use a named graph, it will be easier to describe this
kind of things
... we have to shift the RDF world to recognition of time
nature of data
Ashok: MacTed you have an action on blank node generation
MacTed: it's associated with
that
... blank node should be discouraged when possible
... i'll do my best to address that next week
Souri: you're speaking about
versioning
... DM does not specify anything
... we look at the schema only when you processed the query
<ericP> +1
Souri: so the DM should not reflect that
<ericP> (to souri)
MacTed: speaking about SPARQL-to-SQL?
Souri: yes
MacTed: it's not related
... speaking about RDB to RDF
Souri: it's materialisation?
MacTed: it's part of what I'm saying
<ericP> i don't see how whether instance data has bnodes or URIs in some places impacts the schema mapping
<Zakim> betehess, you wanted to ask when we publish
ericP: if we're not doing
materiazation
... I don't see in any how being BN or not impact a schema
mapping
Ashok: I agree that for me there are different things
<ericP> perhaps a write-up is in order
MacTed: why would you use a
BN?
... only because it's true at this instant
[MacTed arguing]
<ericP> "baseless"?
MacTed: your postulate that your PK will refer forever this tuple is not true
Ashok: hold on, there are quite
different things
... we can keep arguing about that but how is that tied up with
the temporal thing?
... the BN stuff happens just because we don't have a PK
http://www.w3.org/2011/02/16-DM-denotational-rdf-semantics
<ericP> the logic remains consistent either way
<ericP> the question of bnodes is an engineering issue
<ivan> I can witness the validity of Alexandre's statement:-)
<MacTed> DESCRIBE <bnode>
<MacTed> danger.
<ericP> with bnodes or IRIs for subjects of tables with no primary key
<juansequeda> +q
ivan: if not BN, the current
mapping can easily generate a URI
... if it's not BN, how would you generate a URI saying it's
coming from uncertain knowledge
MacTed: even something as "NULL" and a number
<ericP> germain test case: http://www.w3.org/2001/sw/rdb2rdf/wiki/R2RML_Test_Cases_v1#2duplicates0nulls
MacTed: means something now, not later
<ivan> http://example.org/{UUID}
<ericP> how do we address the two entries which are identical in the DB?
Ashok: but the idea was to distinguish between nodes, right?
ivan: using UUID, you have the
unicity
... that's engineering
<Souri> As I explained in my earlier email http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011Feb/0035.html, I think either bNode or (non-reusable) IRI would work fine.
ivan: it just that it won't be
dereferencable
... some people will be unhappy about that
MacTed: if it's not
dereferencable it's a BN
... and there's no point
<Zakim> ericP, you wanted to ask how we would differentiate the two rows in http://www.w3.org/2001/sw/rdb2rdf/wiki/R2RML_Test_Cases_v1#2duplicates0nulls
ericP: I'd to address the test
case I pasted
... re: identical rows in a table
... MacTed please address that, that will help a lot
<Souri> The email I had sent earlier was based on the assumption that we do not materialize (at least) the instance triples.
MacTed: sample answer is: it's bad data and bad scheme
ericP: well, in earlier 80s databases implementation died because of not addressing that
MacTed: this is something you
cannot do well
... there *is* a database id
ericP: if we're doing sparql to
sql, you don't have access to that knowledge
... it's everybody's objective
<ivan> +1 to betehess
<Souri> +1 to ericP re: we are not standardizing SPARQL-to-SQL translation, but we are keeping that in mind
<Souri> and Ashok
ivan: I understand Alex's
remark
... but to be fair, I can still use BN in SPARQL
... we already do that
ok, but in that case, MacTed will have to redefine graph equality through SPARQL + Blank Node :-)
MacTed: if it has a name, it is not a BN
Ashok: we have to create URIs to
distinguish different rows
... it would be useful if you could write something so we can
speak about it next week
MacTed: I'll do my best
Ashok: anyway my understanding
that this "provenance" is a different question
... next item was many-to-many
... byt juansequeda wanted to wait for richard
juansequeda: can speak about it
[juan describes again]
Ashok: should we recognize that as a special case?
juansequeda: last time we decided
to KISS
... I propsoed a switch but people were reluctant
... richard said that with d2rq, people were already asking
about that
<Souri> Is there an issue and/or action item on it?
<ericP> +1 to simple
betehess: KISS
Ashok: so we don't do anything special, right?
ericP: basically yes
<juansequeda> KISS = Keep It Simple Stupid
ericP: if you detect many-to-many, indeed it works, but that's modeling
Ashok: it can be wrong too
ericP: stonebreaker@@ proposed an example where you got it wrong
MacTed: just as ericP said, you
can do wrong
... so it should not be part of the DM
... can be handle later
Ashok: looks like we have a
direction on this
... but we have to wait for richard
... let's see that next week with him
juansequeda: and MacTed can propose something
<boris> betehess is trying to say sth
<Ashok> http://www.w3.org/2001/sw/rdb2rdf/track/issues/10
<juansequeda> ISSUE-10?
<trackbot> ISSUE-10 -- Hash vs Slash -- open
<trackbot> http://www.w3.org/2001/sw/rdb2rdf/track/issues/10
ericP: what is the right way to
describe an identifier
... one implies a 303
... it's an issue for database folks
... cause they have big data
<Ashok> the option is to use a fragment identifier
ericP: so if you go into an extra
GET
... but the payload can be huge
... for no real value
... that's the argument for #
... the argument for / is that it's a better model
... it's easier for local names too
... will write the example down
Ashok: the fragment id semantics is in the media-type
<juansequeda> What are the two possibilities? http://foo.example/DB/People/ID=7#_ vs ??
ivan: if I have a # uri, I expect
the whole before the # to come into the client
... I don't know what it means if this is coming from a
database
... the client is not require to send what is refered behind
the #
<Ashok> to the server
ivan: afaiu, everything has to be dereferencable, I don't know what it means in this case
Ashok: if you're going this
direction, you're requiring JS running on the client
... not ideal
ivan: yeah
<ericP> juansequeda, i think http://foo.example/DB/People/ID=7#_ vs http://foo.example/DB/People/ID=7
juansequeda: wanted to make
clear
... ok, ericP answered :-)
<Zakim> ericP, you wanted to answer implicit cloud-size question and to
juansequeda: if I do a
prefix...
... with the #, I cannot do that
ericP: if we paste an identifier,
we don't want to get the whole database
... we want to identify this or that
<Ashok> ... or whole table
<juansequeda> PREFIX ex <http://foo.example/DB/People/>
<juansequeda> ex:ID=7 vs ex:ID=7#_
ericP: you can use PREFIX to refer to sub parts
juansequeda: I can't write this PREFIX with # :'(
<MacTed> http://foo.example/DB/People/7#_ vs http://foo.example/DB/People/7
<MacTed> can't have equals, so don't spec it to *have* equals
Ashok: someone has to tackle it
<boris> we have to document all of this discussions
<boris> these
<Souri> I am at risk for next week's meeting
<ericP> local names for rdf/xml: http://www.w3.org/TR/2009/REC-xml-names-20091208/#NT-NCName
<ericP> local names for SPARQL: http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115/#rPN_LOCAL
<ericP> +1
<MacTed> thanks, ericP - that'll be helpful
Ashok: let's just Alexandre work
on the document
... we'll speak formally about that later
adjourned
This is scribe.perl Revision: 1.135 of Date: 2009/03/02 03:52:20 Check for newer version at http://dev.w3.org/cvsweb/~checkout~/2002/scribe/ Guessing input format: RRSAgent_Text_Format (score 1.00) Succeeded: s/@@/blank node generation/ Succeeded: s/don't to/want to/ Found Scribe: bertails Found ScribeNick: betehess Present: Ashok Alexandre Boris David Ted._Soeren Souri Regrets: Seema Richard WARNING: No meeting title found! You should specify the meeting title like this: <dbooth> Meeting: Weekly Baking Club Meeting Got date from IRC log name: 22 Feb 2011 Guessing minutes URL: http://www.w3.org/2011/02/22-rdb2rdf-minutes.html People with action items:[End of scribe.perl diagnostic output]