The DoDAF 2 specification introduces a data-centric implementation. Information in the model is at the top-level; information in diagrams reflects information in the underlying model. Diagrams provide a template for information capture.
Relationships between symbols are automatically drawn based on information in the underlying definitions. This data-centric approach is referred to as “representational consistency”: a diagram always consistently represents information in the underlying model, and is consistent with all other diagrams.
This is different from support for earlier versions of the DoDAF spec, which was diagram-centric: relationship information drawn between symbols on diagrams was in some cases accumulated (through utilities) to form model information.
According to the DoDAF 2 specification, “The central core of DoDAF V2.0 is a data-centric approach where the creation of architectures to support decision-making is secondary to the collection, storage, and maintenance of data needed for efficient and effective decisions.”
Representational consistency
Diagram refresh is triggered on diagram open or by selecting Dictionary, Refresh at any time when you have a diagram open.
As a result the following occurs:
Node Symbols
•Are removed if they are no longer defined in the model
Relationship symbols
•Are removed if they are no longer specified/defined by the model.
•Are updated if they have changed (explicit relationships only (see below)
•Added if they can be represented on the diagram, but are not currently.
•When a new symbol is added the relationship symbol part of the refresh is run automatically.
Relationship types in DoDAF 2
DoDAF 2 relationships in System Architect take one of the following forms:
Explicit relationships
A relationship between two definition types is itself a join definition, with properties. The join definition is represented by an appropriate line on a diagram, automatically drawn between symbols representing the related definitions. Likewise, drawing an explicit relationship between two symbols updates appropriate information in their definitions. The join can also be represented by a text-in-cell matrix, where the cell itself is represented by the join definition.
An example of an explicit relationship in DoDAF 2 is the ActivityChangesResource relationship that is drawn between an Activity and any type of Resource on an OV-02 Operational Resource Flow Alternative diagram. The ActivityChangesResource line has properties, such as Information.
Implicit
A relationship that is a simple reference of one definition to another, without any properties of the relationship itself. An implicit relationship is represented by a ListOf definition or OneOf definition property in a definition. System Architect automatically draws an appropriate implicit relationship line between two symbols if either symbol's definition has a ListOf or OneOf property populated with the related definition. Likewise, if an implicit relationship line is drawn between two symbols, the ListOf or OneOf property in one or both of the definitions of those symbols are populated appropriately.
An example of an implicit relationship is the one between Performer and Capability. Performer has a ListOf Capability property, and Capability has a ListOf Performer property.
Inferred relationship
A relationship that exists by navigating relationships between several items. For example, if an Activity is related to a Capability is related to a Performer, then the Activity and the Performer are related. Inferred relationships can be easily computed through the native reporting system, and visualized on Explorer diagrams through the use of Explorer Relationship Reports. Inferred relationships form the basis of Fit-for-purpose views in DoDAF 2 views.