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Synopsis of the Notation

A Decision Requirements Diagram is a graphical representation of a graph that uses the relationships between elements and connectors in the diagram to describe a decision model. The connectors are curiously referred to as requirements in the specification but are represented as lines in the diagram that are used to connect the element into a graph. The following tables lists the elements and connectors that are available from the DRD toolbox and that can be placed onto a diagram to create the Decision Requirement level of the model. Effectively this is the level that would typically be created and maintained by the business analyst, architect or other business personnel.

Elements of a Decision Model

The elements are 2-dimensional shapes that are used to model the various parts of the decision requirements diagram they are available from the DRD toolbox. The elements are the nodes that make up the digraph (directed graph) and are connected by relationships (referred to as requirements) in the form of lines. The elements are used to define a range of concepts from Decisions themselves to  Knowledge Sources. 

Component

Description

Decision

A decision denotes the act of determining an output from a number of inputs, using decision logic which can reference one or more business knowledge models. A decision can be represented in a number of ways, by a Decision Table, Invocation, Context, or Literal Expression.

Business Knowledge Model

A business knowledge model denotes a function encapsulating business knowledge, e.g. as business rules, a decision table, or an analytic model. It serves as a reusable component that could be stored in a library and could be included in any number of Decision Models.

Input Data

An input data element denotes information used as an input by one or more decisions. When enclosed within a knowledge model, it denotes the parameters to the knowledge model. The information defined in the input data element can be structured.

Knowledge Source

A knowledge source denotes an authority for a business knowledge model or decision. The information is external to the decision model and their effect is a continuum from being mandating (regulation or law), controlling (policy), guiding (best practice), influencing (recommendation). The information in the knowledge source vary widely in form from a document, web page, printed material, video or audio content.

Decision Service Expanded

A decision service (expanded) denotes a set of reusable decisions and serves as an invocable element, connected with a knowledge requirement connector to other elements with invocation logic. It provides a mechanism for packaging parts of a decision model into a component or service based architecture and provides an interface that specifies the required information inputs and the resulting outputs. Using this expanded form a modeler can show the details of the service including its encapsulated and output compartments.

Decision Service Collapsed

A decision service (collapsed) denotes a set of reusable decisions and serves as an invocable element, connected with a knowledge requirement connector to other elements with invocation logic. It provides a mechanism for packaging parts of a decision model into a component or service based architecture and provides an interface that specifies the required information inputs and the resulting outputs. Using this collapsed form a modeler can hide the details of the service including its encapsulated and output compartments.

Requirements (Relationships) of a Decision Model

The Decision Model and Notation standard defines three relationships that can be used to connect components in a Decision Requirements diagram. The relationships are directed, and their application creates a digraph (directed graph) connecting the various components of the model. There are two line types used (solid line, dashed line) and three connector end markers (a closed arrowhead, an open arrowhead and a filled circle), which are described in this table.

Information Requirement

An information requirement denotes input data or a decision output being used as one of the inputs of a decision. It therefore specifies the data that is consumed and processed  by the decision to determine the outputs. It is represented as a solid line with a solid arrowhead.

Knowledge Requirement

A knowledge requirement denotes the invocation of a business knowledge model. This indicates that a decision, a decision service or another business knowledge model invokes a business knowledge model to receive its outputs. It is this mechanism that effectively allows a business knowledge model to be reused in different models and contexts.

Authority Requirement

An authority requirement denotes the dependence of a Decision Requirements Diagram (DRD) element on another DRD element that acts as a source of guidance or knowledge. This is a useful mechanism for providing an explanation of the origin of the information that is being used to make the determination of the element making the reference.

Artifacts

There are two types of artifacts listed here, the artifacts that are part of the specification and an additional two elements; one of which is part of the specification but not seen in the notation list and another which is an Enterprise Architect artifact used to visually configure the simulation of a model.

Text Annotation

A text annotation provides a mechanism for a modeler to add explanatory text or a comment to the model. These annotations do not have any modeling semantics but provide informal information related to the entire diagram or to a specific set of elements. They can float in a diagram or be attached by an Association to one or more model elements to indicate their applicability.

Association

An association is a connector that links a text annotation to one or more components in the decision model diagram. It does not have any other semantics beyond this.

Item Definition

An item definition is used to model the structure and the range of values of input data and the outcome of decisions, using a type language such as FEEL or XML Schema. An Item Definition is used to define the structure of the input data and optionally, to restrict the range of allowable values of the data.  Item Definitions can range from a simple single type through to a complex structured type. The core properties of an Item Definition element are accessed via the DMN Expression window.

Simulation Configuration

The DMN simulation configuration is an artifact that is used to specify the configuration of a simulation. It allows the package that contains the decisions to be specified and the input data set that are used for input data. It is not part of the DMN specification but a part of Enterprise Architect's modeling environment and is used to provide a visual mechanism to configure simulations. The artifact must be placed on a diagram that contains decisions that are to be simulated.