IRC log of rdb2rdf on 2011-05-17

Timestamps are in UTC.

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