CTM, TMQL: Let's define 'undef'

One of the TMQL issues is about the role of undefined and its relationship to null in TMQL.

Here I would like to elaborate a bit on the background why null and undef are two different things and why I think that undef should not only be in TMQL, but actually also in CTM.

TMQL Connection

Let us consider a simple query:

select $p / homepage
   $p isa Person

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TM One Language (to rule them all)

Recently Dmitry made some remarks which got me thinking that we do not have yet the correct approach to the property issue:

Properties are a universal mechanism that can be used for many purposes. One of them is mapping from TMDM representation to "nice" CTM representation. RDF mapping is another one. Mapping to object oriented languages is also simplified with properties.

It is definitely true that - if we had an explicit

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CTM != Cobol Topic Maps, Please

I have an increasingly hard time to hide my impatience with the progress, or actually non-progress, or actually regress of the CTM standardization.

Before I kill somebody (and my list is long) and as compensation I followed up the idea to draft a COBOL Topic Maps notation. It was probably born on #topicmaps, maybe also in one of the SC34 meetings. We do weird things there.

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CTM (Compact Topic Maps)

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