Subject: | skip triples if any of S,P,O is null |
http://lists.w3.org/Archives/Public/public-rdb2rdf-comments/2013Sep/0005.html
If a column value (or any of the columns in a rr:template) is null, an r2rml processor should skip the involved triple. If the rr:subjectMap column is null, it should skip all triples in that rr:TriplesMap
There are several tests that require NULL values to be ignored, e.g., this one: http://www.w3.org/2001/sw/rdb2rdf/test-cases/#R2RMLTC0013a
The test result is here: https://bitbucket.org/tobyink/p5-rdf-rdb2rdf/src/6df083243e556e5e8c3044536ab2a4099a3076dc/meta/earl/with-sqlite.ttl?at=RDF-RDB2RDF#cl-626
But I repeated the test, and it fails (returns a row for Alice, which it shouldn’t).
I fixed it in this pull request: https://bitbucket.org/tobyink/p5-rdf-rdb2rdf/pull-request/1/handle-nulls-rrx-languagecolumn/diff
It's together with an extension rrx:languageColumn (approved by Richard Cyganiak). It's my first time using Bitbucket, sorry for mixing two commits in one pull request.