See also: IRC log
<trackbot> Date: 01 December 2009
<scribe> scribe: soeren
<scribe> scribeNick: soeren
approval of minutes
<mhausenblas> http://www.w3.org/2009/11/17-RDB2RDF-minutes.html
approval of the minutes from 17th of Nov
any additions or changes?
<mhausenblas> PROPOSAL: accept minutes
<hhalpin> +1
<mhausenblas> http://www.w3.org/2009/11/24-RDB2RDF-minutes.html
<hhalpin> +1
no objections
all minutes approved
eric suggests the addition of a discussion of the datatypes issue to the agenda
any other additions to the agenda?
<Souri> The latest version (with minor changes) is at http://www.w3.org/2001/sw/rdb2rdf/wiki/images/4/43/RDB2RDF_Map_viaSQL_w3c_final.pdf
start of the presentation
<jsequeda> I apologize for slacking off on the DDL coverage http://www.w3.org/2001/sw/rdb2rdf/wiki/Requirements/DDLCoverage Thanksgiving holiday! I'll get back to that this week!
slide3 describes the architecture
architecture consists of a database and a client side
mapping specification maps relational data into classes and instances
focus is on the client side
SQL engine is not required
if available the SQL language processor generates the RDF schema and RDF instance objects
<hhalpin> Just go to slide 7
<hhalpin> for those without animation
SQL queries specify a transformation
by using foreign and unique key constraints
<Ahmed> It seems lines are mutted.
approach supports comprehensive DBs with views and constraints as well as simple structured data
<hhalpin> Line 31 is muted due to excessive noise, not sure who it is...
if a strong DB is available additional language is not required
soeren: what's meant with no-db
refers only to the client side
the no-db approach works on extracting RDF from JDBC results
an example view is mapped to an RDF class by creating an instance for each row
special columns can indicate class membership
multiple types are possible by creating several rdf:type columns
slide 13
<hhalpin> ?
<MacTed> +1 for page numbers *on* the slides going forward
<MacTed> his PDF viewer is "paper" a/k/a "hardcopy"
<MacTed> title only works when there's no content-change/redrawing
PROPOSAL: by ahmed subsequent presentations should be formated right and contain page numbers
<MacTed> page numbers are *trivial* to add when building presentations
<MacTed> and save lots of trouble
<MacTed> well, nothing's easy in Slidy... ;-)
column aliases are used for mapping to RDF properties
alter view and adding constraints allows to add unique keys
<hhalpin> wondering about "<xyz.com/emp/etype/rdf:type>"
foreign keys are used for mapping to object properties
view names correspond to class names
orri: how to to create instances with data from multiple tables
<hhalpin> So, to summarize (I think!): name of views -> URIs for class, columns in view -> instance URIs, foreign keys -> dataType properties..
orri: what about different types, how are subclass-superclass structures handled
??: is there some development environment
for now just a proposal, no tools available
the approach is very similar to Triplify
SQL should not be reinvented inside the mapping language
its possible to create several rdf:type column aliases
slide 23
different type column aliases are modelled as supproperties of rdf:type
slide 24
<Marcelo> I am also lost ...
<hhalpin> Everyone, re-download the slides if you are missing
<Marcelo> what is the title of the slide?
<MacTed> 38&&
<MacTed> $3
<hhalpin> the slides that says "SPARQL Query: Involving generic rdf:type"
<MacTed> ack. sorry.
<hhalpin> On page 24.
the subproperties of rdf:type help the SPARQL2SQL processor to find the right table to query
slide 26
view names can contain namespace prefixes
slide 27
now, no DB features available at the client side
we have to create a mapping between view names and SQL select queries
slide 30
constraint information is additionally specified
slide 31
mapping of columns to properties is done with a special data structure
slide 32
proposal for a syntax to map SQL selects to classes
slide 33
similar syntax for annotating result column
<hhalpin> Could be a chunk of code at the other end, correct? Just JDBC-compliant code...
<MacTed> started with a VIEW approach, more than with a DB approach...
soeren: both (the no-DB and DB) approach could be easily merged, into one, where the DB version would be just simple SELECT * queries
??: approach appears to be similar to property tables
relational data is not modeled as a triple view
approach is very similar to triplify
less similar to ultrawrap
D2RQ does more i.e. reinventing SQL
we should employ SQL to do relational transformations
inverse properties are important
range information can be derived
from the result column datatypes
slide 35
summary: SQL query is opaque
either views or SQL is mapped to instances
<ericP> jsequeda, care to linger to test something for me?
<jsequeda> ericP: yeah, no problem
ahmed: what's the status of the work?
prototype is not yet ready for the public, but working
orri: did you do measurements?
planned, but will take more time
ahmed: how is efficient query optimization performed
<ericP> 1-
optimization is performed by the SQL optimizer
all the work is pushed down to the DB
indexes can be used as hints
dan: rumour at ISWC - Oracle has a product in this space
oracle supports RDF data already since 3 releases
<mhausenblas> next week is http://www.w3.org/2001/sw/rdb2rdf/wiki/Initial_Round_of_Presentations#SWObjects
<mhausenblas> ericP?
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/classes/tables/ Found Scribe: soeren Inferring ScribeNick: soeren Found ScribeNick: soeren WARNING: No "Present: ... " found! Possibly Present: Ahmed Ashok BenSzekely IPcaller Kingsley_Idehen LeeF MacTed Marcelo OpenLink_Software P15 P30 P31 P32 P34 PROPOSAL RDB2RDF Seema Souri aabb aacc aadd aaee aaff aagg aahh angela_UNITN dan ericP hhalpin iv_an_ru joined jsequeda mMetatomix mhausenblas nunolopes orri scribeNick soeren summary trackbot You can indicate people for the Present list like this: <dbooth> Present: dbooth jonathan mary <dbooth> Present+ amy Found Date: 01 Dec 2009 Guessing minutes URL: http://www.w3.org/2009/12/01-RDB2RDF-minutes.html People with action items: WARNING: Input appears to use implicit continuation lines. You may need the "-implicitContinuations" option.[End of scribe.perl diagnostic output]