TRAK Architecture ViewpointsTRAK Architecture View Content - Tuples, Triples and Orphans
Specifying Architecture View Content - Tuples & Triples
TRAK architecture viewpoint definitions and TRAK architecture views are based on triples i.e. node - relationship - node.
A Triple is formed from a Connector and 2 or 3 Node Elements - Forms a Sentence
An example of a triple is:-
Standard. ISO/IEC/IEEE 42010:2011 has part Requirement. '6 Architecture Frameworks and Architecture Description Languages
A Triple in a TRAK Architecture View Describing a Requirement in ISO/IEC/IEEE 42010
where the subject = Standard. ISO/IEC/IEEE 42010:2011; the predicate (relationship) = 'has part' and the subject = Requirement. '6 Architecture Frameworks and Architecture Description Languages. A triple forms a sentence.
This uses the TRAK metamodel triple Standard has part Requirement used in a MV-03 Requirements & Standards architecture view.
If we want to describe a claim of conformance against a requirement with the reason why the claim is valid we might expand this further.
Describing a Claim of Conformance against a Requirement in ISO/IEC/IEEE 42010
This uses two sets of metamodel triples - tuples:
- Standard has part Requirement has part Requirement and
- Argument supports Claim about Requirement
In order to support the claim of conformance we would then need to prove evidence using:
- Evidence supports Argument and then,
- Evidence proves Claim
In TRAK the more general 'tuple' term is used because this applies to an contiguous number of triples to allow a longer path within the TRAK metamodel to be defined. A triple - a single step path - is still a tuple and it is the smallest possible tuple
A Single Node Describes Nothing - the Smallest Unit of Architecture Description is a Triple
The reason that TRAK uses tuples is:-
- tuples form natural language sentences so anyone can read what they see - you don't need to be a technical what-ML expert. This is one of the reasons why TRAK requires everything to be explicitly named on a view (the other is that this is needed for everyone to read in a consistent way - no guessing or making assumptions about what the architect meant. How many diagrams have you seen with unlabelled lines or rectangles nested inside rectangles ...?).
- a solitary block with no relationship is not a description of any architecture - this requires at least a block and a relationship (to itself) and hence the smallest unit of architecture description is block - reelationship - block
- it is impossible to unambiguously specify a viewpoint or view content using blocks only
- tuples are the basis for assertions and defining meaning and hence TRAK views can be tested, assertions checked and are easy to represent using graphs and semantic notations
- tuples define paths which are the basis for extracting information from your model and allow consistency checks to be specified and verified
Architecture View content can only be Defined Uniquely Using Triples Not Node Elements