- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Thu, 3 May 2012 16:42:49 +0100
- To: Eric Prud'hommeaux <eric@w3.org>
- Cc: W3C RDB2RDF <public-rdb2rdf-wg@w3.org>
On 3 May 2012, at 16:25, Eric Prud'hommeaux wrote: > presumes you can create tables, but yeah, conceptually easier query. (It looks like most databases have a proprietary method of adding the indexes that doesn't require write access to the DB.) > you can even push the symbol generation down: Right. >> The big remaining question is: How to handle this in R2RML? > > Looking for an analog to: > rr:subjectMap [ > rr:column "ROWID"; > rr:termType rr:BlankNode > ]; > I'd propose: > rr:subjectMap [ > rr:termType rr:RowBlankNode > ]; That's an option. Even keeping rr:BlankNode would work — the absence of an rr:column/rr:template/rr:constant might signal that a fresh blank node must be allocated for each row. > Does that complicate things beyond how much a cardinality requirement necessarily complicates things? Well, the spec only needs to define the graph generated by the mapping, so in terms of specification it would be a simple enough change. The implications for implementers are quite significant though. It's a new feature, the implementation costs are not trivial, no existing implementation does this (AFAIK), so there's a certain amount of R&D required to show that it's implementable. Best, Richard
Received on Thursday, 3 May 2012 15:43:20 UTC