See also: IRC log
<trackbot> Date: 26 January 2010
<mhausenblas> scribenick: whalb
<mhausenblas> cygri is with mhausenblas
http://www.w3.org/2010/01/19-RDB2RDF-minutes.html
<mhausenblas> +1
<Ahmed> +1
<mhausenblas> ACTION-18?
<trackbot> ACTION-18 -- Harry Halpin to update web-page and schedule -- due 2010-01-19 -- OPEN
<trackbot> http://www.w3.org/2001/sw/rdb2rdf/track/actions/18
<mhausenblas> close ACTION-18
<trackbot> ACTION-18 Update web-page and schedule closed
<mhausenblas> ACTION-19?
<trackbot> ACTION-19 -- Harry Halpin to put Souri's draft into a WBS poll and notify the WG -- due 2010-01-19 -- OPEN
<trackbot> http://www.w3.org/2001/sw/rdb2rdf/track/actions/19
<hhalpin> will ping souri re e-mail.
<hhalpin> which part of the draft in particular?
<Souri> We have put a write-up (including an XML syntax) on the wiki
<hhalpin> send me the URI
<hhalpin> (looking)
<Souri> under Working docs
<mhausenblas> ACTION-20?
<trackbot> ACTION-20 -- Eric Prud'hommeaux to update http://www.w3.org/2001/sw/rdb2rdf/wiki/LinkedDataAspects#Linked_Data_Principles to say 'MUST allow to..." -- due 2010-01-26 -- OPEN
<trackbot> http://www.w3.org/2001/sw/rdb2rdf/track/actions/20
<mhausenblas> close ACTION-20
<trackbot> ACTION-20 Update http://www.w3.org/2001/sw/rdb2rdf/wiki/LinkedDataAspects#Linked_Data_Principles to say 'MUST allow to..." closed
<mhausenblas> ACTION-21
<mhausenblas> close ACTION-21
<trackbot> ACTION-21 Update http://www.w3.org/2001/sw/rdb2rdf/wiki/LinkedDataAspects#Well-known_Entities to reflect discussion (3 cases) closed
<mhausenblas> ACTION-22?
<trackbot> ACTION-22 -- Eric Prud'hommeaux to add Ahmed's plan to the Wiki -- due 2010-01-26 -- OPEN
<trackbot> http://www.w3.org/2001/sw/rdb2rdf/track/actions/22
<mhausenblas> close ACTION-22
<trackbot> ACTION-22 Add Ahmed's plan to the Wiki closed
<mhausenblas> ACTION-23
<mhausenblas> ACTION-23?
<trackbot> ACTION-23 -- Richard Cyganiak to update http://www.w3.org/2001/sw/rdb2rdf/wiki/LinkedDataAspects#Provenance re today's discussion -- due 2010-01-26 -- OPEN
<trackbot> http://www.w3.org/2001/sw/rdb2rdf/track/actions/23
<Seema> Souri I will follow up with you on this
ahmed: main topic is how we continue forward, give an outline and set direction
<hhalpin> sounds good to me
ahmed: two sub-teams, another team for linked data needed
<hhalpin> well, sort of.
soeren: no further linked data group needed, included in both other sub-teams
ahmed: wants linked data area to
be covered anyway
... need more people commited to sub-teams
... how are we going to proceed?
<hhalpin> +1 status reports
<Souri> This was the URL: http://www.w3.org/2001/sw/rdb2rdf/wiki/RDB-to-RDF_mapping:_A_SQL-based_Approach
ahmed: are teams going to give
status reports of e.g. 15mins?
... how are we going to show progress?
<hhalpin> http://neurocommons.org/page/Common_Naming_Project
<hhalpin> http://www.okkam.org/
<hhalpin> http://linkeddata.org/
hhalpin: suggest that each group has a member dealing with the different aspects of linked data, etc.
<hhalpin> i'd also suggest that we have a session with the HCLS group
mhausenblas: we should focus on mapping stuff in the first phase, other members supporting both teams re. linked data
<hhalpin> as they have interaction for NeuroCommons Common Naming Project
mhausenblas: whenever there is a need from one of the groups to get some input on linked data topics the experts should chime in
<hhalpin> ericP?
<hhalpin> He's the staff contact for HCLS
hhalpin: also input from the life science domain, probalby from ericp
<mhausenblas> ACTION: ericP to take care of the HCLS statement [recorded in http://www.w3.org/2010/01/26-RDB2RDF-minutes.html#action01]
<trackbot> Sorry, couldn't find user - ericP
<hhalpin> hmm
<hhalpin> let me look
soeren: two proposals: oracle
created one and soeren tried to distill another one, wanted to
align efforts
... not yet talked to each of the other groups
... suggestions for possible syntax of the mapping:
<soeren> http://www.w3.org/2001/sw/rdb2rdf/wiki/R2RML_SQL_View_Annotation
soeren: called SQL View
Annotation, intention is to add syntax for mapping
language
... syntax: db conn needs to be established, namespaces +
prefixes
... two distinguished namespaces: base namespace for creating
data instance items
... optional schema namespace: properties, classes
... could be overwritten by custom definitions
... table definition is the core, most important part
... R2RMap current single syntactical element, first parameter
basically a relation identifier
... second element: path used to create linked data entity
identifiers
... additional parameters are optional
... third element: reference to a class (rdfs, owl) used to
make instances of this specific clas (optional parameter)
... remaining parameters: definitions for each of the columns
in the relation (from param1)
... they are all optional
... if omitted the column name is used for creating
identifiers
... syntax is inspired by triplify
... additional issues: user defined output processing
functions, static metadata, attribute-value tables, named
graphs,
... update logs, provenance (triplify approach could also be
applied here)
... a lot of work already done on how to tackle these
issues
... core is r2rmap syntax
... as a staring point that can be refined later on
<Zakim> mhausenblas, you wanted to note on Test Cases
mhausenblas: start thinking about
test cases: specify sample input and output
... ideally a set of test cases is created/made available
ahmed: alignment with ashok?
soeren: contacted ashok/oracle,
waiting for responses
... discussion will take 2-3 more weeks
<Souri> Soren, not sure if you got our email from Friday -- we wanted to find out times that would be convenient to you
ahmed: two teams working
together, is there a need for a leader of the sub-teams?
... responsible for communication, coordination, not a
technical leader
mhausenblas: person in charge should also have reporting responsibility
ahmed: any volunteers or suggestions?
orri: we should do something that
substantially relies on sql
... fine with something that's compatible to sql views as long
as it works out in the end
<Souri> Did anyone get a chance to review the XML syntax we had posted last week? (special case simplification with auto-mapping is always possible)
<hhalpin> For soundness and completeness, I would defer to Marcelo or at least have him go over the draft :)
<Marcelo> sure, I can do it :-)
<hhalpin> ericP: I think it's left stuff to specify mapping SPARQL to SQL
<mhausenblas> scribenick: hhalpin
soeren: but SPARQL constructs are
very limited in expressivity
... assigning results of a computation to a new variable
... build a string by concating 2 others
... i.e. firstname+lastname concat for a URI
<cygri> hhalpin, its richard
ericP: can't do that.
cygri: And we are not sure about
SPARQL 1.1
... we will have use-cases outside of SPARQL construct
... this will require a bit of work
... if it is possible
ericP: understood
orri: it would seem to me
... that we need to things in sql
... but we should take sparql 1.1 as a given
ericP: but the point
remains
... that a bit of sql
... the commonality is still more expressive than even sparql
1.1
... what do we save about this use-cases?
Ahmed: the main issue with SQL
view
... is you have to "touch" the database
<whalb> soeren: disagrees
<whalb> ... no need to touch the database
<Souri> I disagree
<whalb> cygri: several database problems with horrible performance
<Souri> agree with Soren
<whalb> soeren: customised mapping approach still could be done, optimised subqueries will be faster
<whalb> orri: sql dbs will be fine
<whalb> ... query gets unusual when mapping sparql to sql
<whalb> ... in prinicple should be fine
<mhausenblas> scribenick: whalb
cygri: sparql to sql translation is hard for the user to optimise
Dan: manipulation can be done on internal representations
cygri: you can use base tables if that is all you need
<juansequeda> yes
cygri: need to rely on optimiser
in database if complex query
... not same effort as doing optimisation on other side
ahmed: subqueries not a
problem
... problem is at the end you get sql datatypes
cygri: not a problem, soeren's
syntax proposal covers that basically
... can be easily done outside db
ahmed: why classify this approach
as sql view
... translating sql data outside the db
soeren: there is need for a
mapping engine finally
... sql (view) annotation approach
... sql engine already does mapping from sql data to data
ahmed: disagrees, you get back
sql datatypes if mapping is done outside
... why call this approach sql view mapping
cygri: sql output is turned into
rdf triples
... transforming to sql view is done inside db
<ericP> SPARQL queries tranlated to SQL
<Souri> The SQLdefString is the one that is employed directly against the host db (i.e., the data source)
cygri: transformation from three
col sql result is simple work done outside
... mapping is inside the db
ahmed: view is defined term in
sql world
... would not call that approach sql view, misuse of
terminology
<hhalpin> We can call it something else I imagine...
orri: column is the predicate on the row, multi-col views ok
ahmed: sql view means that data
is updated automatically
... the last mentioned approach does not need any special
optimisation
cygri: still a problem for
specific db systems, e.g. mysql
... simple looking queries can perform poorly
<mhausenblas> we need to wrap up soon, we're on the top of the hour
ahmed: which subqueries do not
perfom well?
... mysql usually only has drawbacks in transactions, updates,
...
... difference if change in db is needed or not
... we need to support both cases
<Seema> Oracle presentation covers both "db" and "no db" cases
<hhalpin> hmmm...
ahmed: interested to get to know difficult subqueries for mysql
soeren: question seems not to be
important
... there are some issues with every db
<ericP> http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2010Jan/att-0050/RDB2RDFTest.scala
soeren: but there has been spent a lot of time on db development
ericp: interested if those sql queries could make troubles
<hhalpin> i think we can continue for a bit till discussion ends
ahmed: subquery is no issue at
any level
... problem is the optimiser for specific types of queries
<mhausenblas> I'd love to see a write-up of today's discussion :)
ahmed: create a list of typical queries generated from sparql to sql to figure out the difficult ones
<mhausenblas> Michael: I like today's discussion - eventually we start to disagree
ahmed: start collecting cases on the wiki
ericp: sql generated from rdb2rdf translations, sql that is a "show stopper"
ahmed: would like to see an approach that does not touch the db
<ericP> GeneratedSQL and PotentialSQLIssues
<mhausenblas> thanks to ericP for kicking-off the Wiki stuff
souri: oracle presentation mentioned that in the case db is not touched
<Ahmed> Bye.
<hhalpin> bye
<mhausenblas> 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 0.99) Succeeded: s/soeren/cygri/ Succeeded: s/?:/Dan:/ Found ScribeNick: whalb Found ScribeNick: hhalpin Found ScribeNick: whalb Inferring Scribes: whalb, hhalpin Scribes: whalb, hhalpin ScribeNicks: whalb, hhalpin Default Present: +1.512.471.aaaa, whalb, mhausenblas, hhalpin, +49.322.222.0.aabb, soeren, cygri, +035385271aacc, nunolopes, MacTed, EricP Present: +1.512.471.aaaa whalb mhausenblas hhalpin +49.322.222.0.aabb soeren cygri +035385271aacc nunolopes MacTed EricP Regrets: Angela Ben Agenda: http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2010Jan/0047.html Found Date: 26 Jan 2010 Guessing minutes URL: http://www.w3.org/2010/01/26-RDB2RDF-minutes.html People with action items: ericp[End of scribe.perl diagnostic output]