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Components of Decision Requirements Diagrams

The elements modeled in Decision Requirements graphs (DRGs) and Decision Requirements diagrams (DRDs) are Decision, Business Knowledge Model, Input Data, Knowledge Source and Decision Service. The dependencies between these elements express three kinds of requirement - Information, Knowledge and Authority.

Components of Decision Requirements Diagrams

This table summarizes the notation for all components of a Decision Requirements diagram.

Component

Description

See also

Decision

A Decision element denotes the act of determining an output from a number of inputs (Input Data or Decision), using decision logic expressed as Literal Expressions, Decision Tables, Invocations or Boxed Context.

DMN Expression Editor

Business Knowledge Model

A Business Knowledge Model denotes a reusable module of decision logic represented by a function, which includes zero, one or more than one parameter.

Input Parameter Values for Simulation

Decision Service (expanded)

A Decision Service can enclose a set of reusable decisions that are invoked internally - for example, by another Decision or Business Knowledge Model - or externally - for example, by a BPMN Process.

A good practice is to use a diagram to describe a single expanded Decision Service.

Decision Service

Decision Service (collapsed)

If a Decision Service element serves as an invocable element, connected with knowledge requirements to other elements with invocation logic, we can hide the details of the Decision Service to focus on the decision hierarchies in the big picture.

Decision Service

Input Data

An Input Data element denotes information used as an input to one or more Decisions.

InputData

Item Definition

An Item Definition is used to define the type and structure of data items used in the decision model. It is primarily referenced by Input Data elements as a basis for the type and structure of data expected to be input. It can also be referenced for setting the structure for an output.

The Item Definition contains Data Sets that provide sets of values useful when performing varied simulations.

ItemDefinition

Knowledge Source

A Knowledge Source element denotes an authority for a Business Knowledge Model or Decision.

Information Requirement

An Information Requirement denotes Input Data or Decision output being used as input to a Decision.

Knowledge Requirement

A Knowledge Requirement denotes the invocation of a Business Knowledge Model or Decision Service.

Authority Requirement

An Authority Requirement denotes the dependence of a DRG element on another DRG element that acts as a source of guidance or knowledge.