- From: Souripriya Das <souripriya.das@oracle.com>
- Date: Tue, 04 Oct 2011 11:41:10 -0400
- To: dguardiola@quinode.fr
- CC: public-rdb2rdf-comments@w3.org
- Message-ID: <4E8B2916.80109@oracle.com>
Re-sending with the proper email addresses. -- Souri. Souripriya Das wrote: > Thanks for your comments. We will discuss them in the Working Group meetings and then get back to you. > > However, I wanted to comment on couple of the points you have raised > > Clarification about ISSUE-57: > > > * The second option does NOT require support for *ALL* syntaxes > for RDF. It just requires support for AT LEAST ONE such syntax. > The difference is that the syntax does NOT HAVE TO BE Turtle. > That is, one implementation may decide to support only N-Triples > syntax and another implementation may support Turtle syntax, and > so on. The basic idea is that a mapping document must be a valid > RDF graph that uses the R2RML vocabulary properly. But, the > syntax in which this RDF graph is expressed is immaterial. > Different implementations may have support for different syntax(es). > > Regarding the question about "Sec 9: Assigning Triples to Named Graphs": > > > * Yes, you need to use R2RML view for the scenario you described. > > Thanks, > - Souri. > > On RDB Direct mapping > > 2.2 Foreign keys referencing candidate keys > A syntax using a comma separating the two keys "key1,key2" is mentioned twice in this part of the document, while everywhere else the "#ref-key1.key2" convention is used. > > On R2RML : > > ISSUE-57 : > Asking for any RDF syntax support should be optional. > Given the availibility of RDF converters and librairies to make Turtle from anyhting, asking for implementations to support all syntaxes is excessive. > To allow time for adoption and real-life experiments with the vocabulary, the Turtle syntax should be the only mandatory syntax for processors, so that exchange, learning and adoption would not be impaired by syntax-related side questions. > > > ISSUE-66 : > I read the exchanges and the minutes where the final resolution was taken. > I think this decision is a pity : if you look from the point of view of future R2RML end-users , translation tables are a common pattern, which is present, for example in most web development frameworks or CMSs. > Anyone making SQL database knows it's better to use integers columns instead of verbose labels in order to : > - speed up queries > - allow the renaming of these columns labels easily > - avoid typos when these columns are also keys (when there's no foreign key constraint : think of MyISAM, probably one of the most common DB storage) > > The use of SKOS here is a false question : it's true this looks like a "controlled vocabulary" situation, but I'd follow the argument stating that having properties like rr:value, rr:term is simpler for RDF newbies. I mean, a vocabulary choice question should not prevent you to provide this kind of simple feature. > Allowing the table to be linked elsewhere is important too, but could be added later, as could be more complex mapping techniques. > But removing this simple tool, a 1:1 code-to-string or code-to-URI table, from being part of the recommandation would send IMHO a bad signal to newcomers , like "hey, they didn't even think of a straightforward way to do that?" > Having to do pre-queries in a R2RML view just to fetch some labels in a separate table (that perhaps doesn't even exists, the labels list being hardcoded in the application code) is not really an answer. > > > 9 Assigning Triples to Named Graphs: > I'm thinking of a case where using a [rr:template ...] would not suffice to express the graph URI, how could I use a rule to say "if column A == "abcd" then use g:graph1", or more complex regex rules. > Would I have to use a R2RML view if I want to do that? > > > > -- > Dominique Guardiola, QUINODE > . http://www.quinode.fr/ > . Tel : 04.27.86.84.37 > . Mob : 06.15.13.22.27 >
Received on Tuesday, 4 October 2011 15:43:19 UTC