Relax Constraint AASD-120 for SMT allow idShort in SML

[BirgitBoss]

Is your feature request related to a problem? Please describe.
For Submodel Template creation it is helpful to have an idShort for the element type within the SML.
This is mainly the case for SML of SMC or SML because there are separate tables for SMC and SML. For properties it is more difficult.
See discussion in admin-shell-io/submodel-templates#65

Constraint AASd-120: idShort of submodel elements being a direct child of a SubmodelElementList shall not be specified.

could be relaxed to

Constraint AASd-120: idShort of submodel elements being a direct child of a SubmodelElementList shall not be specified within Submodels with kind=Instance.

Describe alternatives you've considered

• do not relax
  -- instead create ConceptDescriptions with idShort of the corresponding elements

• remove completely, i.e. also allow idShort in Submodels with kind=Instance for better readability

AASd-120 was a further restriction of
Constraint AASd-117: idShort of non-identifiable Referables not being a direct child of a SubmodelElementList shall be specified.

[BirgitBoss]

TF Part 1 2024-06-12 Decision Proposal:
remove AASd-120

[BirgitBoss]

Accepted in principle by Workstream AAS Spec. 2024-06-13
Comments:

• within a Submodel with kind=Instance idShorts need to be unique. For SMT there is only exactly one element allowed to be part of the SML.
• However, in idShortPath idShort of SML elements shall not be used (because you cannot rely that the idShort exists)
• In ValueOnly Format of API idShort will not be used (it is an JSON array)
• even consider to make idShort mandatory for SML elements as well (then it could be used in idShortPath as well) However, this is not backward compatible
• Part 2 affected as well, is there a need to add a corresponding comment in Part 2

TF AAS Part 1 will discuss this issue again and make a proposal