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admin-shell-io / questions-and-answers

This repository aims for providing answers to often asked questions in the context of the Asset Administration Shell.
https://admin-shell-io.github.io/questions-and-answers/
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Using RDF as an interchange format #59

Closed hvags closed 2 years ago

hvags commented 2 years ago

RDF in the form of Turtle files is presented in the documentation as one option for presentation of AAS data for semantic purposes. However the "Details of the Asset Administration Shell" document refers to the AAS serializations packaged in an AASX file as "either json or xml". I would be interested in knowing if this is intentional or if RDF/Turtle should be considered equal to json or xml for exchange purposes.

StenGruener commented 2 years ago

15.11.2021: according to "Details of the Asset Administration Shell" mapping to RDF is defined and possible. However, AASX Package Explorer and AASX Server currently do not support RDF encoding. However, RDF encoding is supported by https://github.com/admin-shell-io/java-serializer.

BirgitBoss commented 2 years ago

We consider rdf to be a suitable format for more enhanced applications, e.g. requiring complex queries. So it is just that the focus is a little bit different when to use which format.

hvags commented 2 years ago

Thank you both for your feedback. One more question I had regarding this is whether the serialization/deserialization to/from RDF/Turtle is lossless. That is, does the RDF data model support all structures in the AAS or are there any caveats there?

Also @StenGruener - am I wondering if your 'todo' tag means we'll be seeing the rdf serialization implemented in C# within the AASX Package Explorer / Server repos...

StenGruener commented 2 years ago

@hvags 'todo' in this repository means to add this question to the FAQ ;)

Leaving the the answer to the main question to more knowledgeable colleagues.

arnoweiss commented 2 years ago

When using the java-serializer and java-model in conjunction, the de/serialization is lossless. The spec (V3RC01) was slightly unclear in some instances but the implementation has ensured completeness.

StenGruener commented 2 years ago

@BirgitBoss @MichaelHoffmeisterFesto could you confirm the statement about "lossless conversion" or name anyone who is able to answer?

BirgitBoss commented 2 years ago

When using the java-serializer and java-model in conjunction, the de/serialization is lossless. The spec (V3RC01) was slightly unclear in some instances but the implementation has ensured completeness.

@alw-iwu could you please let us know what was unclear so that we can make the spec. more precise. Thank you!

BirgitBoss commented 2 years ago

@BirgitBoss @MichaelHoffmeisterFesto could you confirm the statement about "lossless conversion" or name anyone who is able to answer?

As @alw-iwu stated: it is "lossless". If it is not, I would consider it a bug. @sebbader : what do you say?