Hi, I was doing some comparison of relational databases and Linked Data and ran into the problem of representing an equivalent of database NULL in RDF.
I was surprised I haven't found any material or discussion on this topic (found only [1]) - is there some?. I believe it would be beneficial if this question was answered somewhere for future reference. I started a question on Stack Overflow [2] where I think it will be easier to discover and so that this list won't get polluted. I'm aware of the open world assumption in RDF, but NULL or a missing value can have several interpretations, for example: - value not applicable (the attribute does not exist or make sense in the context) - value uknown (it should be there but the source doesn't know it) - value doesn't exist (e.g. year of death for a person alive) - value is witheld (access not allowed) I would like to known whether there is some *standard or generally accepted* way of distinguishing these cases. If you have an answer, please put it on [2], is possible. Thanks in advance, Jan Michelfeit [1] http://lists.w3.org/Archives/Public/public-rdf-wg/2011Nov/0167.html [2] http://stackoverflow.com/q/16873174/2032064
