Re: RDB2RDF WG agenda for 2012-05-01 meeting 1600 UTC

sorry my "late" regrets.
it's holiday here

Boris

On May 1, 2012, at 2:51 PM, Michael Hausenblas wrote:

> All,
> 
> Please find below the agenda for our today's conference call.
> 
> Cheers,
> 	Michael
> 
> 
> ---------------------------------------------------------
> AGENDA Teleconference
> W3C RDB2RDF Working Group telephone conference 2012-05-01
> ----------------------------------------------------------
> *16:00-17:00 UTC*
> Local time:
> 
> 
> http://timeanddate.com/worldclock/fixedtime.html?month=05&day=01&year=2012&hour=16&min=00&sec=0
> 
> 
> Bridge US: +1-617-761-6200 (Zakim)
> Conference code: 7322733# (spells "RDB2RDF")
> IRC channel : #RDB2RDF on irc.w3.org:6665 W3C
> ---------------------------------------------------------
> 
> 
> Chair: Michael
> Scribe: Ashok (?)
> 
> 
> 1. Admin
> 
> PROPOSAL: Accept the minutes of last meeting http://www.w3.org/2012/04/24-RDB2RDF-minutes.html
> 
> 
> 
> 2. Implementability for tables w/o primary key 
> 
> + http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0030.html
> + http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0036.html
> + http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0019.html
> 
> PROPOSAL: In the DM spec, replace the following text:
> 
> [[
> If the table has no primary key, the row node is a fresh blank node that is unique to this row.
> ]]
> 
> with this:
> 
> [[
> If the table has no primary key, the row node is a blank node. Distinct blank nodes MUST be generated for rows with distinct column values. For duplicate rows with identical values, implementations SHOULD generate a fresh blank for each duplicate row (resulting in a non-lean RDF graph [RDF Semantics]). However, if the underlying database system does not provide any means to reliably differentiate among the rows, then implementations MAY re-use the same blank node for multiple duplicate rows (resulting in a lean RDF graph). Implementations SHOULD document and advertise their chosen behavior.
> ]]
> 
> 
> 
> 3. XSD mapping for binary columns (xsd:hexBinary vs. xsd:base64Binary)
> 
> + http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0020.html
> 
> 
> PROPOSAL: Binary datatypes like BLOB and VARBINARY should be mapped to xsd:hexBinary instead of xsd:base64Binary.
> 
> 
> 
> 4. DM cannot be implemented as an R2RML mapping (period encoding)
> 
> http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0021.html
> 
> 
> SUMMARY of the proposal: “Direct Mapping: Change %-escaping rules to be compatible with R2RML. Change two delimiter characters to ones that are safe under these rules.”
> 
> 
> Details of the change proposal as of http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0070.html (contains also the motivation/justification)
> 
> 
> 
> 5. Fixing an omission in R2RML: syntax of blank node labels
> 
> + http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0060.html
> 
> 
> PROPOSAL: Change Section 11.2 of R2RML http://www.w3.org/TR/2012/CR-r2rml-20120223/#generated-rdf-term) from:
> 
> [[
> If the term type is rr:BlankNode: Return a blank node whose blank node identifier is the natural RDF lexical form corresponding to value.
> ]]
> 
> to:
> 
> [[
> If the term type is rr:BlankNode: Return a blank node that is unique to the natural RDF lexical form corresponding to value.
> 
> NOTE: RDF syntaxes and RDF APIs generally represent blank nodes with blank node identifiers. But the characters allowed in blank node identifiers differ between syntaxes, and not all characters occurring in value may be allowed, so a bijective mapping function from values to valid blank node identifiers may be required. The details of this mapping function are implementation-dependent, and an R2RML processors may have to use different functions for different output syntaxes or access interfaces. Strings matching the regular expression [a-zA-Z_][a-zA-Z_0-9-]* are valid blank node identifiers in all W3C-recommended RDF syntaxes.
> ]]
> 
> 
> 
> 6.  Using non-existing column in mapping 
> 
> + http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0018.html
> 
> 
> Section 6 of the R2RML spec (http://www.w3.org/TR/2012/CR-r2rml-20120223/#triples-map) states:
> 
> [[
> The referenced columns of all term maps of a triples map (subject map, predicate maps, object maps, graph maps) MUST be column names that exist in the term map's logical table.
> ]]
> 
> 
> PROPOSAL: Any referenced columns (that is, the columns mentioned in rr:column, rr:template, etc.) that don't exist in the rr:sqlQuery or table are treated simply as being NULL, rather than being considered an error. Perhaps the case could still be treated as a warning:
> 
> [[
> Processors MAY warn mapping authors if a referenced column does not exist in the logical table.
> ]]
> 
> 
> 
> 7. Unnamed columns in rr:sqlQuery 
> 
> + http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012Apr/0017.html
> 
> 
> Section 5.2 of the R2RML spec (http://www.w3.org/TR/2012/CR-r2rml-20120223/#r2rml-views) states:
> 
> [[
> Any columns in the SELECT list derived by projecting an expression MUST be named.
> ]]
> 
> 
> PROPOSAL: Above to be replaced with an informative note:
> 
> [[
> Note: Any columns in the SELECT list derived by projecting an expression should be explicitly named because otherwise they cannot be referenced in the rest of the mapping.
> ]]
> 
> 
> 
> 8. AOB
> 
> 
> --
> Dr. Michael Hausenblas, Research Fellow
> DERI - Digital Enterprise Research Institute
> NUIG - National University of Ireland, Galway
> Ireland, Europe
> Tel.: +353 91 495730
> WebID: http://sw-app.org/mic.xhtml#i
> 
>

Received on Tuesday, 1 May 2012 17:10:09 UTC