Re: Representing NULL in RDF

Hi Jan,

That's because nulls are generally not represented in Linked Data by design.  One "represents" a null by failing to include the relationship.  


On Jun 3, 2013, at 4:38, Jan Michelfeit <> wrote:

> 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]
> [2]

Received on Monday, 3 June 2013 13:44:54 UTC