15:52:04 RRSAgent has joined #rdb2rdf 15:52:04 logging to http://www.w3.org/2011/05/17-rdb2rdf-irc 15:52:06 RRSAgent, make logs world 15:52:06 Zakim has joined #rdb2rdf 15:52:08 Zakim, this will be 7322733 15:52:08 ok, trackbot; I see SW_RDB2RDF()12:00PM scheduled to start in 8 minutes 15:52:09 Meeting: RDB2RDF Working Group Teleconference 15:52:09 Date: 17 May 2011 15:52:19 Agenda: http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0046.html 15:55:19 network is back 15:56:11 ahh good, everyone is happy 15:58:51 SW_RDB2RDF()12:00PM has now started 15:58:58 +juansequeda 15:58:59 juansequeda has joined #rdb2rdf 15:59:12 Zakim, code? 15:59:12 the conference code is 7322733 (tel:+1.617.761.6200 tel:+33.4.26.46.79.03 tel:+44.203.318.0479), MacTed 15:59:19 +OpenLink_Software 15:59:27 Zakim, OpenLink_Software is temporarily me 15:59:27 +MacTed; got it 15:59:29 Zakim, mute me 15:59:29 MacTed should now be muted 15:59:46 Zakim, mute me 15:59:46 juansequeda should now be muted 15:59:49 dmcneil has joined #RDB2RDF 15:59:58 +mhausenblas 16:00:15 Zakim, unmute me 16:00:15 juansequeda should no longer be muted 16:00:26 regrets+ Ivan 16:00:32 +dmcneil 16:00:35 regrets+ Eric 16:00:45 regrets+ Alexandre 16:00:46 someone was asking about R2RML implementation timing in a recent call.... can add a first-cut for Virtuoso to that list, now anticipated for June if not sooner 16:01:02 present+ Ted 16:01:05 present+ Juan 16:01:09 present+ David 16:01:13 present+ Michael 16:01:32 Zakim, cygri is with me 16:01:32 +cygri; got it 16:01:38 Zakim, nuno will be with me 16:01:38 I don't understand 'nuno will be with me', mhausenblas 16:01:44 soeren has joined #RDB2RDF 16:01:49 RRSAgent, draft minutes 16:01:49 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 16:01:58 RRSAgent, make the logs public, please 16:01:58 I'm logging. I don't understand 'make the logs public', mhausenblas. Try /msg RRSAgent help 16:02:04 RRSAgent, make logs public, please 16:02:11 + +1.862.137.aaaa 16:02:20 nunolopes has joined #RDB2RDF 16:02:30 zakim, aaaa is soeren 16:02:30 +soeren; got it 16:02:33 present+ Soeren 16:02:35 Zakim, nunolopes is with mhausenblas 16:02:35 +nunolopes; got it 16:02:42 present+ Nuno 16:02:47 RRSAgent, draft minutes 16:02:47 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 16:02:59 zakim, mute me 16:03:00 juansequeda should now be muted 16:03:12 Zakim, pick a victim 16:03:12 Not knowing who is chairing or who scribed recently, I propose juansequeda (muted) 16:03:32 i can scribe 16:03:44 scribenick: dmcneil 16:03:48 Chair: Michael 16:04:02 Ashok has joined #rdb2rdf 16:04:09 +Ashok_Malhotra 16:04:18 present+ Ashok 16:04:18 thanks :) 16:04:25 +Souri 16:04:31 RRSAgent, draft minutes 16:04:31 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 16:04:49 present+ Souri 16:04:52 Seema has joined #rdb2rdf 16:05:07 present+ Seema 16:05:26 +Seema 16:05:35 Souri has joined #rdb2rdf 16:06:05 RRSAgent, draft minutes 16:06:05 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 16:06:15 present+ cygri 16:06:28 zakim, who is on the phone? 16:06:28 On the phone I see juansequeda (muted), MacTed (muted), mhausenblas, dmcneil, soeren, Ashok_Malhotra, Souri, Seema 16:06:30 mhausenblas has mhausenblas, cygri, nunolopes 16:06:35 Topic: Admin 16:06:48 PROPOSAL: Accept the minutes of last meeting http://www.w3.org/2011/05/10-rdb2rdf-minutes.html 16:07:25 RESOLUTION: minutes accepted by working group 16:07:47 Topic: LC planning 16:07:48 last call planning... 16:07:57 http://www.w3.org/2001/sw/rdb2rdf/wiki/Main_Page#Countdown_to_Proposed_Recommendation 16:08:27 ACTION-125? 16:08:27 ACTION-125 -- Ashok Malhotra to draft Wiki page with LC sprint time line with Sep 2011 LC -- due 2011-05-17 -- OPEN 16:08:27 http://www.w3.org/2001/sw/rdb2rdf/track/actions/125 16:08:32 close ACTION-125 16:08:33 ACTION-125 Draft Wiki page with LC sprint time line with Sep 2011 LC closed 16:09:31 michael: do the editors agree with the timeline? 16:09:42 zakim, unmute me 16:09:42 juansequeda should no longer be muted 16:10:09 souri: need to think about how many issues, and how many "sticky" issues 16:10:28 ashok: we can close it, so we don't take any until last call 16:10:43 there are 9 open issues, none look very difficult 16:11:30 michael: there are more than just open issues, last time we reviewed them and concluded we needed to resolve a couple per call 16:11:34 -juansequeda 16:11:52 what does it mean to "close it", working group members are encouraged to raise issues 16:12:16 +??P2 16:12:36 ashok: meant to close current issues then not accept more until after last call is published 16:12:37 Zakim, ??P2 is me 16:12:37 +juansequeda; got it 16:13:51 q+ 16:14:04 michael: maybe we could call it "freezing" the list 16:14:44 cygri: we know there are issues to be resolved and a timeframe to do it in, as long as we make progress and knock off issues each week then we are on track 16:15:13 so we should focus on closing issues 16:15:19 q+ to state it is not about the current issues 16:15:28 ack juansequeda 16:15:29 juan: so by Sept 1 all issues need to be closed? 16:15:45 ashok: yes, either closed or postponed 16:15:57 juan: so after last call we can still close issues 16:16:30 ashok: are there any open issues on Direct Mapping? 16:16:36 juan: yes 16:16:41 ack me 16:16:41 mhausenblas, you wanted to state it is not about the current issues 16:17:11 michael: the issue with freezing the list is not about current issues but new issues 16:17:30 q? 16:17:54 cygri: i think if we freeze the queue now then we prevent ourselves from hearing about issues 16:18:01 -juansequeda 16:18:20 q+ 16:18:24 Zakim, unmute me 16:18:24 MacTed should no longer be muted 16:18:29 implementors will find issues or ask for clarification, we need to hear about these 16:18:34 +1 to Richard's comment 16:18:44 privera has joined #RDB2RDF 16:18:48 RRSAgent, draft minutes 16:18:48 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 16:19:01 if we really run out of time then we acknowledge hearing the feedback but delay addressing it until after last call 16:19:09 maybe will need to freeze later 16:19:12 +??P2 16:19:24 ack MacTed 16:19:40 ted: agrees with Richard 16:19:58 michael: do we need a resolution for this? 16:20:04 +??P21 16:20:08 Zakim, mute me 16:20:08 MacTed should now be muted 16:20:12 ashok: no 16:20:19 present+ Percy 16:20:26 Zakim, mute me 16:20:26 sorry, privera, I do not know which phone connection belongs to you 16:20:32 Topic: Action Items 16:20:33 michael: on to action items 16:20:50 Zakim, ??P21 is privera 16:20:50 +privera; got it 16:20:55 ACTION-127? 16:20:55 ACTION-127 -- Richard Cyganiak to write up a proposal to resolve ISSUE-32 based on today's discussion -- due 2011-05-17 -- OPEN 16:20:55 http://www.w3.org/2001/sw/rdb2rdf/track/actions/127 16:20:56 Zakim, mute me 16:20:56 privera should now be muted 16:21:43 close ACTION-127 16:21:43 ACTION-127 Write up a proposal to resolve ISSUE-32 based on today's discussion closed 16:21:51 http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0029.html 16:21:55 thread starts here ^ 16:22:19 david's version: http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0030.html 16:23:04 another proposal from me: http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0035.html 16:23:18 "col1=>col2" 16:23:41 rr:joinCondition [ rr:child "col1"; rr:parent "col1" ]; 16:24:58 souri: was thinking that David's proposal isolates each column in a separate property, which makes it easier to deal with special characters in the column names 16:25:09 e.g. if a column was named "foo=>" 16:25:55 +Marcelo 16:26:02 cygri: agrees that approach is clearly modelled and avoids certain syntax issues 16:26:04 present+ Marcelo 16:26:10 RRSAgent, draft minutes 16:26:10 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 16:26:29 escaping comment intersects with another thread of discussion regarding special characters 16:26:56 beleives that "=>" is not valid in un-quoted SQL identifiers 16:27:14 Oracle: create table "a=>b" (a int); 16:27:38 SELECT "foo=>" FROM table; 16:27:39 this means that we would have to quote the column name again anyway 16:28:10 rr:column "\"foo=>\"" 16:28:13 "\"foo\"" 16:28:47 rr:joinCondition "\"col1=>\"=>col2" 16:29:15 so the handling of special characters is not a distinguishing characteristic of the alternatives 16:30:04 Marcelo has joined #rdb2rdf 16:30:37 cygri: although it is very verbose, if there is group agreement then we can go that way 16:30:49 souri: appreciates the clarity of the more verbose approach 16:31:31 PROPOSAL: resolve ISSUE-32 as per http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0030.html 16:32:08 +1 16:32:18 ±0 16:32:24 michael: any objections? 16:32:34 +1 16:33:04 Ashok has joined #rdb2rdf 16:33:24 RESOLUTION: working group resolves ISSUE-32 as per http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0030.html 16:33:45 michael: now we need an action to write this in the editors draft 16:34:12 cygri: i can do it 16:34:21 ACTION: Richard to implement ISSUE-32 as resolved today (based on http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0030.html) 16:34:21 Created ACTION-130 - Implement ISSUE-32 as resolved today (based on http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0030.html) [on Richard Cyganiak - due 2011-05-24]. 16:34:51 ACTION-129? 16:34:51 ACTION-129 -- Ashok Malhotra to check re DB2 and SQL-Server for ISSUE-35 (case sensitivity of SQL identifiers) -- due 2011-05-24 -- OPEN 16:34:51 http://www.w3.org/2001/sw/rdb2rdf/track/actions/129 16:34:59 close ACTION-129 16:34:59 ACTION-129 Check re DB2 and SQL-Server for ISSUE-35 (case sensitivity of SQL identifiers) closed 16:35:46 ashok: almost all databases follow the SQL standard: column names and table names are case insensitive except when double quoted 16:35:58 in which case they are handled in a case sensitive manner 16:36:26 RRSAgent, draft minutes 16:36:26 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 16:36:31 SQL Server is the only one that is different, you can configure it to behave differently than the standard 16:36:58 q+ 16:36:59 so we probably need to say that you should follow the guidelines of your database 16:37:03 ack Souri 16:37:28 souri: does the SQL standard allow double quotes in the identifiers? 16:37:55 oracle allows everything else (as long as it is quoted) except double quotes 16:38:00 ACTION-126? 16:38:00 ACTION-126 -- Souripriya Das to implement ISSUE-18 resolution and make sure that all class and property names are meaningful -- due 2011-05-24 -- OPEN 16:38:00 http://www.w3.org/2001/sw/rdb2rdf/track/actions/126 16:38:42 souri: not done yet, discussion was about having "Class" as a suffix on the class names in the R2RML spec 16:39:05 to avoid naming conflicts with the property names 16:39:25 so they do no just differ by the case of the first character 16:39:40 so we can keep "Class" at the end of the class named 16:39:45 s/named/names/ 16:40:00 cygri: we can avoid similar names with ad-hoc tweaking of one of the terms 16:40:09 using slightly different wording 16:40:31 example: class => rr:SubjectMapClass and property => rr:subjectMap 16:40:34 there are examples from other ontologies where they differ only in the case, so while it is not good, we would not be the first spec to do this 16:41:17 Zakim, unmute me 16:41:17 MacTed should no longer be muted 16:41:25 Michael: how about rr:SubjectMap and rr:mapsTo 16:41:59 or mapsSubject or ... 16:42:11 similar names for class and property are confusing..not particularly thrilled with that approach 16:42:33 ted: agrees with using different terms (it is madness to have just case differences) 16:42:43 Zakim, mute me 16:42:43 MacTed should now be muted 16:42:45 ACTION-128? 16:42:45 ACTION-128 -- Michael Hausenblas to find the resolution re what SQL and SPARQL we address and make this explicit core requirements in the UCR document -- due 2011-05-31 -- OPEN 16:42:45 http://www.w3.org/2001/sw/rdb2rdf/track/actions/128 16:42:48 +q 16:42:56 ack dmcneil 16:44:00 :) 16:44:07 q+ 16:44:44 ack Souri 16:44:46 souri: could make properties verbs 16:45:22 will keep the request for clarity in mind as new proposed names are assembled 16:45:35 Topic: Open Issues 16:45:35 moving on to issues 16:45:48 ISSUE-41? 16:45:48 ISSUE-41 -- Define how rr:column, rr:template, etc. handle NULL column values -- raised 16:45:48 http://www.w3.org/2001/sw/rdb2rdf/track/issues/41 16:46:09 http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0042.html 16:47:52 on ISSUE-41 there were several +1 votes for not producing triples if a column was null 16:48:01 on the mailing list 16:48:45 +q 16:48:53 +1 for option 2 16:49:02 souri: ok with that option, but there is another option where we could produce a NULL literal 16:49:15 +1 for option 2 16:49:20 +1 for option 2 16:49:39 ashok: what would a NULL literal mean in RDF? 16:50:18 Zakim, unmute me 16:50:18 MacTed should no longer be muted 16:50:25 ack dmcneil 16:50:28 -1 option 2 16:50:52 q+ 16:51:20 ack MacTed 16:51:55 q+ 16:52:05 dmcneil: a couple of clarifications: so a template with many columns, any of them being null means that the triple would be produced? 16:52:23 ack cygri 16:52:28 if users need to map NULL db values to default values then they would need to do it in a SQL query? 16:52:46 :hasAge "" . 16:52:50 ted: NULL values can have meaning in the relational world 16:53:14 cygri: blank nodes correspond to unknown values 16:53:28 ted: no, blank nodes are for unnamed values 16:53:47 XML Schema has a concept called NIL which corresponds to the SQL NULL 16:54:26 cygri: a blank node is an existential value that says something exists, but nothing more about it 16:54:34 bNode => existential, :hasAge _:b1 . 16:54:52 discussion degrades 16:55:51 souri: blank node allows a value to be identified without providing other details (e.g. if that blank node never appears again in the graph) 16:56:15 ted: NULL values may have meaning in a relational schema 16:56:17 +q 16:56:27 q? 16:56:42 ashok: that requires us to create a special "value" to correspond to NULL 16:56:57 that means we are adding to RDF 16:57:06 ted: no, just adding to R2RML and Direct Mapping 16:57:07 q+ 16:57:24 ack dmcneil 16:57:46 q? 16:57:48 q- 16:58:13 :cell :prop "DB_NULL" 16:58:24 dmcneil: users could define their schema specific expectations for NULL in a SQL query 16:58:32 SQL => select y from tab WHERE x IS NULL 16:58:33 ted: that requires users to have too sophisticated of a model 16:58:46 :hasAge UNDEFINED 16:59:12 ?s ?p "NULL" 16:59:16 ?s ?p UNDEFINED 17:00:05 juan: so the output should include the NULLs? 17:00:09 person(name, age) 17:00:15 person(Juan, NULL) 17:00:30 :id1 "Juan". 17:00:42 :id1 NULL ==> is this what you want? 17:01:06 :id1 "Bob" 17:01:07 :id2 NULL 17:01:14 Should we support an option for a TriplesMap: 1) NULL => disappears 2) NULL => translated to "" (a simple literal) [is ""^^xsd:integer legal in RDF?] 17:01:30 cygri: in Direct Mapping I think it might make sense to preserve the NULLs 17:01:42 but in R2RML a query can be used to handle NULLs 17:02:00 michael: out of time 17:02:13 q+ 17:02:14 cygri: maybe ted can write a counter-proposal 17:02:50 ack Souri 17:03:11 souri: how to treat a NULL in a table may vary from table to table 17:03:24 from that point of view, we could always create a view in R2RML 17:03:33 q? 17:03:34 but that is a longer way of doing things 17:03:49 so what if R2RML included a property defining what value to produce for NULL 17:03:58 this can vary between triplesmaps 17:04:35 ?: but what about Direct Mapping 17:04:43 that is Marcelo 17:04:44 ted: yes, I think so 17:05:08 document the default, and provide an easy way to change it 17:05:33 ashok: but on Direct Mapping we have said there are no switches, just one algorithm 17:05:42 ted: then it must preserve nulls 17:06:11 souri: given the RDF I should be able to reconstruct the table 17:07:06 so the Direct Mapping by default (and since there are no switches) so it must preserve the NULLs 17:07:13 cygri: then the way to go is a blank node 17:07:26 there is something there but we don't know what it is 17:07:49 souren: NULL in the db says there is nothing there 17:08:12 s/souren/soeren/ 17:08:19 ashok: it is the lack of a value 17:08:42 Is ""^^xsd:integer a valid RDF value? 17:08:51 soeren: consider an integer column: 0 is different than NULL 17:08:59 so creating no triple for this makes sense 17:09:08 ted: but it is schema dependent 17:09:33 cygri: in SQL, NULL is a special thing, it is not simply "there is no value", it can be used in different ways 17:09:48 sometimes it is used to indicate "there is a value, but we don't know it" 17:09:58 soeren: then we could say that sometimes NULL means 100 17:10:07 most common interpretation is "there is no value" 17:10:20 despite the fact that it can be abused 17:10:30 ted: the most common understanding is to abuse it 17:10:38 soeren: then ignore it because it is nonsense 17:10:39 q+ 17:10:45 q? 17:10:58 cygri: agree that R2RML should ignore it, because you can customize it 17:11:08 ack Souri 17:11:12 zakim, mute me 17:11:12 soeren should now be muted 17:11:36 -??P2 17:11:59 juansequeda_ has joined #rdb2rdf 17:12:00 souri: should be able to look at output triples to conclude that we have a column in the the table (when that column only has NULL values) 17:12:06 (talking about Direct Mapping) 17:12:11 +juansequeda 17:12:41 michael: can we have a proposal for ISSUE-41? 17:12:59 ISSUE-41 is for R2RML actually, right? 17:13:42 i think the counter-proposal is to default it to suppress, but add a property to specify what vbalue to use for null 17:13:46 on a per triplesmap basis 17:14:54 michael: we can write to Pat (?) 17:15:12 souri: how do we know the type of the column if there are only NULL values? 17:15:20 cygri: also consider empty tables 17:15:39 must look at schema to preserve schema information (looking at data does not work) 17:17:49 question for Pat: is a blank node an accurate representation of a NULL value from a relational database? 17:18:11 ACTION: Hausenblas to write mail to Pat regarding ISSUE-41 - is a blank node an accurate representation of a NULL value from a relational database? 17:18:11 Created ACTION-131 - Write mail to Pat regarding ISSUE-41 - is a blank node an accurate representation of a NULL value from a relational database? [on Michael Hausenblas - due 2011-05-24]. 17:18:29 -Souri 17:18:31 -privera 17:18:32 -Ashok_Malhotra 17:18:33 -dmcneil 17:18:34 -mhausenblas 17:18:35 -Seema 17:18:35 -soeren 17:18:36 -juansequeda 17:18:36 -MacTed 17:18:39 -Marcelo 17:18:40 SW_RDB2RDF()12:00PM has ended 17:18:42 Attendees were juansequeda, MacTed, mhausenblas, dmcneil, cygri, +1.862.137.aaaa, soeren, nunolopes, Ashok_Malhotra, Souri, Seema, privera, Marcelo 17:18:48 [meeting adjourned] 17:19:12 RRSAgent, draft minutes 17:19:12 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html mhausenblas 17:22:57 trackbot, end telecon 17:22:57 Zakim, list attendees 17:22:57 sorry, trackbot, I don't know what conference this is 17:22:58 RRSAgent, please draft minutes 17:22:58 I have made the request to generate http://www.w3.org/2011/05/17-rdb2rdf-minutes.html trackbot 17:22:59 RRSAgent, bye 17:22:59 I see 2 open action items saved in http://www.w3.org/2011/05/17-rdb2rdf-actions.rdf : 17:22:59 ACTION: Richard to implement ISSUE-32 as resolved today (based on http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011May/0030.html) [1] 17:22:59 recorded in http://www.w3.org/2011/05/17-rdb2rdf-irc#T16-34-21 17:22:59 ACTION: Hausenblas to write mail to Pat regarding ISSUE-41 - is a blank node an accurate representation of a NULL value from a relational database? [2] 17:22:59 recorded in http://www.w3.org/2011/05/17-rdb2rdf-irc#T17-18-11