Re: Proposal for ISSUE-32, curly braces in joinCondition

> This also raises the question of how NULL columns are handled in general by
> R2RML. As far as I can tell the current draft of the recommendation does not
> address this (although it does address the case of NULL values with the
> graphColumn property). It seems to me that the spec should explicitly state
> how NULL columns are to be handled in the case of the rr:column and
> rr:template properties. Possible answers to this question are:
>
> 1) throw an error if a column is null
> 2) do not produce a triple if a referenced column is null
> 3) ??
>

I created ISSUE-41 for this
http://www.w3.org/2001/sw/rdb2rdf/track/issues/41

-David