15:43:51 <RRSAgent> RRSAgent has joined #RDB2RDF
15:43:51 <RRSAgent> logging to http://www.w3.org/2012/04/24-RDB2RDF-irc
15:43:53 <trackbot> RRSAgent, make logs world
15:43:53 <Zakim> Zakim has joined #RDB2RDF
15:43:55 <trackbot> Zakim, this will be 7322733
15:43:55 <Zakim> ok, trackbot; I see SW_RDB2RDF()12:00PM scheduled to start in 17 minutes
15:43:56 <trackbot> Meeting: RDB2RDF Working Group Teleconference
15:43:56 <trackbot> Date: 24 April 2012
15:44:11 <mhausenblas> Agenda: http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0024.html
15:44:15 <mhausenblas> Chair: Michael
15:44:27 <mhausenblas> scribenick: mhausenblas 
15:44:35 <mhausenblas> RRSAgent, draft minutes
15:44:35 <RRSAgent> I have made the request to generate http://www.w3.org/2012/04/24-RDB2RDF-minutes.html mhausenblas
15:44:41 <mhausenblas> RRSAgent, make logs public
15:46:08 <mhausenblas> regrets+ Ivan
15:46:15 <mhausenblas> present+ Michael
15:46:22 <mhausenblas> present+ Richard
15:57:53 <Ashok> Ashok has joined #rdb2rdf
15:58:25 <Zakim> SW_RDB2RDF()12:00PM has now started
15:58:32 <Zakim> +mhausenblas
15:59:02 <Zakim> +Ashok_Malhotra
15:59:13 <cygri> cygri has joined #rdb2rdf
15:59:16 <mhausenblas> present+ Ashok
15:59:22 <boris> boris has joined #rdb2rdf
15:59:31 <mhausenblas> scribenick: Ashok
15:59:41 <mhausenblas> Zakim, cygri is with me
15:59:41 <Zakim> +cygri; got it
16:00:35 <Zakim> +??P2
16:00:45 <boris> zakim, ??P2 is me
16:00:45 <Zakim> +boris; got it
16:01:00 <joerg> joerg has joined #RDB2RDF
16:01:04 <mhausenblas> present+ Boris
16:01:09 <mhausenblas> Zakm, who's here?
16:01:12 <Zakim> +[OpenLink]
16:01:15 <mhausenblas> Zakim, who's here?
16:01:15 <Zakim> On the phone I see mhausenblas, Ashok_Malhotra, boris, [OpenLink]
16:01:16 <Zakim> On IRC I see joerg, boris, cygri, Ashok, Zakim, RRSAgent, mhausenblas, MacTed, betehess, iv_an_ru_, trackbot, ericP
16:01:16 <Zakim> mhausenblas has mhausenblas, cygri
16:01:21 <mhausenblas> present+ Ted
16:01:25 <MacTed> Zakim, [OpenLink] is temporarily me
16:01:25 <Zakim> +MacTed; got it
16:01:46 <Zakim> +??P12
16:01:54 <nunolopes> nunolopes has joined #rdb2rdf
16:02:07 <mhausenblas> Zakim, nunolopes is with me
16:02:07 <Zakim> +nunolopes; got it
16:02:10 <joerg> joerg joined
16:02:27 <dmcneil> dmcneil has joined #RDB2RDF
16:02:28 <mhausenblas> Zakim, ??P12 is joerg 
16:02:28 <Zakim> +joerg; got it
16:02:34 <mhausenblas> present+ Joerg
16:02:54 <Zakim> + +1.314.395.aaaa
16:03:06 <Ashok> Topic:  Minutes of last meeting
16:03:12 <mhausenblas> Zakim, aaaa is dmcneil 
16:03:12 <Zakim> +dmcneil; got it
16:03:17 <mhausenblas> present+ David
16:03:22 <mhausenblas> Zakim, who's here?
16:03:22 <Zakim> On the phone I see mhausenblas, Ashok_Malhotra, boris, MacTed, joerg, dmcneil
16:03:24 <Zakim> On IRC I see dmcneil, nunolopes, joerg, boris, cygri, Ashok, Zakim, RRSAgent, mhausenblas, MacTed, betehess, iv_an_ru_, trackbot, ericP
16:03:24 <Zakim> mhausenblas has mhausenblas, cygri, nunolopes
16:03:40 <mhausenblas> RRSAgent, draft minutes
16:03:40 <RRSAgent> I have made the request to generate http://www.w3.org/2012/04/24-RDB2RDF-minutes.html mhausenblas
16:03:51 <mhausenblas> PROPOSAL: Accept the minutes of last meeting  http://www.w3.org/2012/04/03-RDB2RDF-minutes.html
16:04:03 <boris> +1
16:04:09 <Ashok> Minutes approved without objection
16:04:28 <juansequeda> juansequeda has joined #rdb2rdf
16:04:57 <mhausenblas> ericP are you gonna join us?
16:05:01 <Zakim> + +575737aabb
16:05:07 <juansequeda> Zakim, aabb is me
16:05:07 <Zakim> +juansequeda; got it
16:05:23 <mhausenblas> present+ Juan
16:05:28 <mhausenblas> present+ Marcelo
16:05:44 <mhausenblas> Topic: Implementation feedback
16:06:32 <cygri> q+
16:06:45 <mhausenblas> ack cygri 
16:07:07 <mhausenblas> + DM cannot be implemented as an R2RML mapping http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0021.html
16:07:08 <mhausenblas> + XSD mapping for binary columns http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0020.html
16:07:09 <mhausenblas> + implementability for tables w/o primary key http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0019.html
16:07:10 <mhausenblas> + using non-existing column in mapping http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0018.html
16:07:11 <mhausenblas> + Unnamed columns in rr:sqlQuery http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0017.html
16:07:30 <Ashok> Richard:  There is an issue about lang nodes identifiers ...
16:07:49 <juansequeda> Zakim, who is on the phone
16:07:49 <Zakim> I don't understand 'who is on the phone', juansequeda
16:07:55 <Ashok> s/is/is also/
16:07:59 <mhausenblas> Zakim, who's here?
16:07:59 <Zakim> On the phone I see mhausenblas, Ashok_Malhotra, boris, MacTed, joerg, dmcneil, juansequeda
16:08:02 <Zakim> On IRC I see juansequeda, dmcneil, nunolopes, joerg, boris, cygri, Ashok, Zakim, RRSAgent, mhausenblas, MacTed, betehess, iv_an_ru_, trackbot, ericP
16:08:02 <Zakim> mhausenblas has mhausenblas, cygri, nunolopes
16:08:11 <mhausenblas> RRSAgent, draft minutes
16:08:11 <RRSAgent> I have made the request to generate http://www.w3.org/2012/04/24-RDB2RDF-minutes.html mhausenblas
16:08:23 <Zakim> +EricP
16:08:26 <MacTed> q+
16:08:32 <mhausenblas> present+ Nuno
16:08:50 <mhausenblas> q?
16:09:01 <seema> seema has joined #rdb2rdf
16:09:01 <Ashok> s/lang/blank/
16:09:48 <Zakim> +Souri
16:09:56 <mhausenblas> present+ Souri
16:10:06 <mhausenblas> present+ Eric
16:10:10 <Souri> Souri has joined #rdb2rdf
16:10:13 <Zakim> + +1.603.897.aacc
16:10:15 <cygri> http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0019.html
16:10:17 <mhausenblas> RRSAgent, draft minutes
16:10:17 <RRSAgent> I have made the request to generate http://www.w3.org/2012/04/24-RDB2RDF-minutes.html mhausenblas
16:10:22 <Ashok> + implementability for tables w/o primary key http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0019.html
16:10:23 <cygri> "DM: implementability for tables w/o primary key"
16:10:31 <mhausenblas> Zakim, aacc is seema 
16:10:31 <Zakim> +seema; got it
16:10:39 <mhausenblas> present+ Seema
16:10:42 <mhausenblas> RRSAgent, draft minutes
16:10:42 <RRSAgent> I have made the request to generate http://www.w3.org/2012/04/24-RDB2RDF-minutes.html mhausenblas
16:11:08 <mhausenblas> Zakim, who's here?
16:11:08 <Zakim> On the phone I see mhausenblas, Ashok_Malhotra, boris, MacTed, joerg, dmcneil, juansequeda, EricP, Souri, seema
16:11:11 <Zakim> On IRC I see Souri, seema, juansequeda, dmcneil, nunolopes, joerg, boris, cygri, Ashok, Zakim, RRSAgent, mhausenblas, MacTed, betehess, iv_an_ru_, trackbot, ericP
16:11:11 <Zakim> mhausenblas has mhausenblas, cygri, nunolopes
16:12:13 <mhausenblas> q?
16:12:47 <Ashok> Richard:  The multiple blank nodes cannot be told apart in queries, etc.
16:12:55 <ericP> q+
16:13:16 <mhausenblas> ack MacTed 
16:13:20 <mhausenblas> ack ericP 
16:13:21 <mhausenblas> q?
16:15:44 <Ashok> q+
16:16:50 <Souri> Example: two rows in a single table T1<lender,borrower,amount,tdate>: R1 => <John,Mary,100,01-Jan-2012>, R2 => <John, Mary,100,01-Jan-2012>
16:16:53 <cygri> SELECT * { ?s ?p ?o }
16:18:21 <cygri> T1<borrower,amount>
16:18:34 <cygri> <John,10>, <John,10>
16:20:06 <cygri> SELECT ROWID AS s, "T1/borrower" AS p, borrower AS o FROM T1 UNION SELECT ROWID AS s, "T1/amount" AS p, amount AS o
16:20:49 <Souri> ROWNUM ?
16:21:03 <mhausenblas> ack Ashok 
16:21:05 <mhausenblas> q?
16:21:16 <cygri> ROWNUM works in this simple case but not in more complex ones AFAIK
16:21:47 <MacTed> q+
16:22:19 <mhausenblas> ack MacTed 
16:22:28 <Ashok> Ashok:  can you write an appropriate SPARQL query?  Translating to SQL is not part of our spec.
16:22:46 <Ashok> s/can/Can/
16:25:06 <Ashok> Richard:  The fact that the nodes are indistinguishable is a problem ... this will show up in programming language
16:25:19 <Ashok> Ted:  That is a schema problem
16:25:32 <Souri> q+ to ask if this is the correct DM based generated triples: _:b1  ex:borrower  ex:John ; ex:amount 10 . _:b2  ex:borrower  ex:John ; ex:amount 10 .
16:25:48 <juansequeda> Souri, you are correct
16:26:13 <juansequeda> q+ to ask Richard what is his proposal?
16:26:29 <mhausenblas> ack Souri 
16:26:29 <Zakim> Souri, you wanted to ask if this is the correct DM based generated triples: _:b1  ex:borrower  ex:John ; ex:amount 10 . _:b2  ex:borrower  ex:John ; ex:amount 10 .
16:26:30 <mhausenblas> q?
16:26:31 <juansequeda> souri, yes!
16:26:46 <Ashok> Richard:  The translation from SPARQL to SQL cannot be done
16:26:55 <juansequeda> it needs to be distinct in order to be query preserving. Otherwise, you couldn't do aggregation
16:27:58 <Ashok> Richard:  I would recommend we relax the requirement and implementations can add identifying information
16:28:05 <juansequeda> q+
16:28:46 <mhausenblas> ack juansequeda 
16:28:46 <Zakim> juansequeda, you wanted to ask Richard what is his proposal? and to 
16:28:47 <mhausenblas> q?
16:29:43 <Ashok> Juan:  You would lose query preservation
16:33:07 <Souri> q+
16:33:23 <Ashok> Richard:  You should generate a blank node for each row or a blank node for each set of unique values
16:33:44 <Souri> Unless I am mistaken, unique key of a row could be NULL
16:33:49 <mhausenblas> q?
16:34:04 <Souri> zakim, ack me
16:34:04 <Zakim> I see no one on the speaker queue
16:34:05 <Ashok> Q+
16:34:21 <mhausenblas> ack Ashok 
16:34:59 <Souri> q+
16:35:18 <mhausenblas> ack Souri 
16:35:37 <Ashok> Ashok:  Isn't this a real corner case
16:36:34 <Ashok> Souri:  Problem is we are crossing row boundaries
16:36:34 <mhausenblas> Michael: I tend to agree. It seems like a corner case to me as well. This just means we've experienced a limitation of our specs during CR.
16:36:36 <ericP> q+ to say you can always fall back to materializing for this case
16:36:57 <cygri> ericP, doesn't help you with Jena
16:37:24 <mhausenblas> Michael: If we can agree on corner case, we should discuss what would need to happen that we isolate this (add warning, remove TC, etc.)
16:37:26 <mhausenblas> q?
16:37:45 <ericP> could you propose an API invocation to address?
16:37:47 <dmcneil> seems like you could also use "count" in SQL to see how many duplicates there are
16:38:05 <mhausenblas> ack ericP 
16:38:05 <Zakim> ericP, you wanted to say you can always fall back to materializing for this case
16:38:06 <cygri> q+ to ask Souri how to write that view in Core SQL 2008
16:39:35 <juansequeda> PROPOSAL: If you have a db that has a table that does not have a primary key, we recommend to materialize the RDF
16:40:19 <cygri> juansequeda, -1. the only tables without PKs that I see in practice are gigantic ones, like log tables.
16:40:33 <MacTed> -1 to dropping the test case
16:40:33 <MacTed> +1 to warning "RDB data with these characteristics cannot be (usefully) dynamically (direct) mapped; materiliazation (replication + transformation) is recommended."
16:40:49 <juansequeda> +1 to MacTed
16:41:00 <MacTed> s/materiliazation/materialization/
16:41:10 <mhausenblas> q?
16:41:11 <Ashok> Michael:  We need to decide if this is a corner case and can be isolated or we change the spec
16:42:53 <mhausenblas> q?
16:43:47 <ericP> or they are inefficient in that case, which may well be acceptable
16:44:31 <MacTed> q+
16:45:01 <cygri> PROPOSAL: "if the table has no primary key, the row node is a blank node. whether this blank node is identical to other blank nodes is undefined."
16:45:25 <mhausenblas> ack cygri 
16:45:25 <Zakim> cygri, you wanted to ask Souri how to write that view in Core SQL 2008
16:45:32 <Ashok> Richard, where would you put those words?
16:45:51 <ericP> suppose the T1 table is large and i want to not fully materialize
16:45:51 <ericP> SELECT ?owes { ?s <borrower> "Bob" ; <amount> ?owes } =>
16:45:51 <ericP> SELECT borrower AS p, amount AS o FROM T1 WHERE borrower="Bob" then add the bnodes and a type triple for each of those bnodes
16:46:12 <ericP> you only process the selected rows
16:46:24 <mhausenblas> ack MacTed 
16:47:28 <mhausenblas> q?
16:47:47 <Ashok> Ted: Richard has made an argument based on a SPARQL query ... that is out of our charter ... a warning is sufficient 
16:49:10 <dmcneil> +q
16:49:22 <mhausenblas> ack dmcneil 
16:49:24 <Ashok> Ted:  The RDF group is questioning the model
16:50:11 <Ashok> David:  Do you assume that 1 SPARQL query leads to 1 SQL query?
16:50:17 <Ashok> Richard:  No
16:50:28 <mhausenblas> RRSAgent, draft minutes
16:50:28 <RRSAgent> I have made the request to generate http://www.w3.org/2012/04/24-RDB2RDF-minutes.html mhausenblas
16:50:56 <Ashok> David:  Outlines a solution using cursor to create distinguishable blank nodes
16:52:24 <Ashok> Michael:  Do we argee this is a corner case?
16:52:35 <Ashok> s/argee/agree/
16:53:01 <juansequeda> This is not a bug. it's an implementation issue. It can be implemented... maybe inefficiently, but it can
16:53:18 <Ashok> Richard:  It is a corner case but we need to fix the bug ... I suggest a 1 sentence change
16:53:27 <cygri> juansequeda, it cannot be implemented except when dumping
16:53:41 <juansequeda> cygri, you can do post processing afterwards. 
16:53:44 <cygri> juansequeda, some implementers are not interested in dumping the db
16:54:36 <Ashok> Eric:  I'm still working on trying to create a case where this is a problem
16:54:37 <MacTed> I think that sentence is not sufficient, if we're going in that direction.  I'm not entirely opposed to a change in that direction (optional blank-node distinction over multiple identical-content rows).
16:55:28 <mhausenblas> q?
16:56:04 <cygri> q+
16:56:11 <mhausenblas> ack cygri 
16:57:14 <Ashok> Richard: It is a corner case but we need to fix it
16:57:43 <mhausenblas> q?
16:58:22 <Ashok> ... we are not mapping to a proper RDF graph because the nodes are not distinguishable
16:58:42 <cygri> MacTed, RDF concepts says: "Given two blank nodes, it is possible to determine whether or not they are the same."
16:59:16 <mhausenblas> q?
16:59:16 <ericP> [[
16:59:19 <ericP> DB: T1<borrower,amount,date> T2<name,address>
16:59:19 <ericP> SELECT ?borrower ?amount ?address {
16:59:19 <ericP> _:t1 <T1#date> ?date ; <T1#borrower> ?borrower ; <T1#amount> ?amount .
16:59:19 <ericP> _:t2 <T2#name> ?borrower ; <T2#address> ?address
16:59:21 <ericP> FILTER (?date < "2012-01-01"^^xsd:date)
16:59:24 <ericP> } =>
16:59:26 <ericP> SELECT T1.borrower, T1.amount, T2.address
16:59:29 <ericP> FROM T1, T2
16:59:31 <ericP> WHERE T1.date < "2012-01-01"
16:59:34 <ericP> AND T1.borrower=T2.name
16:59:36 <ericP> ]]
16:59:41 <ericP> (still not arriving at something i can't implement)
17:01:02 <juansequeda> q+ to ask why is this long. It's just a difference between lean and an not lean RDF graph http://www.w3.org/TR/rdf-mt/#graphdefs
17:01:34 <mhausenblas> ack juansequeda 
17:01:34 <Zakim> juansequeda, you wanted to ask why is this long. It's just a difference between lean and an not lean RDF graph http://www.w3.org/TR/rdf-mt/#graphdefs
17:02:04 <mhausenblas> q?
17:02:30 <Ashok> Juan:  We need to preserve cardinality
17:02:47 <cygri> juansequeda, good observation. and note that leanification doesn't change the semantics
17:02:54 <Souri> [removing bNodes from Eric's query] ?x <T1#date> ?date ; <T1#borrower> ?borrower ; <T1#amount> ?amount . ?y <T2#name> ?borrower ; <T2#address> ?address . FILTER (?date < "2012-01-01"^^xsd:date)
17:04:29 <MacTed> +1 base64 change to hex
17:05:04 <mhausenblas> ACTION: Richard to come up with concrete example re "DM: implementability for tables w/o primary key"
17:05:05 <trackbot> Created ACTION-205 - Come up with concrete example re "DM: implementability for tables w/o primary key" [on Richard Cyganiak - due 2012-05-01].
17:05:14 <mhausenblas> (meeting adjourned)
17:05:19 <Zakim> -joerg
17:05:24 <Zakim> -seema
17:05:26 <Zakim> -dmcneil
17:05:39 <mhausenblas> trackbot, end telecon
17:05:39 <trackbot> Zakim, list attendees
17:05:39 <Zakim> As of this point the attendees have been mhausenblas, Ashok_Malhotra, cygri, boris, MacTed, nunolopes, joerg, +1.314.395.aaaa, dmcneil, +575737aabb, juansequeda, EricP, Souri,
17:05:39 <juansequeda> mhausenblas, so what about turning in test cases. we were suppose to do that next week. I guess it is postponed
17:05:42 <Zakim> ... +1.603.897.aacc, seema
17:05:47 <trackbot> RRSAgent, please draft minutes
17:05:47 <RRSAgent> I have made the request to generate http://www.w3.org/2012/04/24-RDB2RDF-minutes.html trackbot
17:05:48 <trackbot> RRSAgent, bye
17:05:48 <RRSAgent> I see 1 open action item saved in http://www.w3.org/2012/04/24-RDB2RDF-actions.rdf :
17:05:48 <RRSAgent> ACTION: Richard to come up with concrete example re "DM: implementability for tables w/o primary key" [1]
17:05:48 <RRSAgent>   recorded in http://www.w3.org/2012/04/24-RDB2RDF-irc#T17-05-04