Decision Requirement Diagram

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What is Decision Requirement Diagram (DRD)?

Decision Requirement Diagram (DRD) is a diagram that can be created following Decision Model and Notation (DMN), which is an open standard notation for modeling decisions that are based on logic, data, and processes. It was developed by Object Management Group (OMG) in 2014. It provides meta-model, notation, and semantics for decision modeling. This is a complimentary notation to BPMN for modelling of operational decisions and business rules.

What is a Decision

decision is an act of determining an output value, based on a number of input values, using logic defining how the output is determined from the inputs. A decision model is a model in a specific area that defines decision requirements and decision logic.

In DMN, A decision is modeled at two levels:

  1. Decision Requirement
  2. Decision Logic

Decision Requirement is a high-level model that defines one or more Decision Requirement Diagrams (DRDs), which makes a Decision Requirement Graph (DRG). At the Decision Logic level, the different details of the implementation of logically related to each node (e.g., Decision) in the DRG is defined. This logic can have any implementation, but as far as DMN is concerned the Decision Table is a standard way of logic implementation.

Knowledge Source

One of the benefits of modeling in DMN is that, not only can it model the actual decision-making process at different levels, but also that you can model (link) the documentation, references and authorities around these. The Knowledge Source is for that purpose. Also, it can be used to check the impact of change if these sources are changed.

Decision Logic Level

At this level, the implementation of decisions and business knowledge can be linked to each node at the decision requirement level. These implementations can vary based on your needs, product capabilities and other factors (e.g., your familiarity with a specific type of logic: Decision Table, Tree, etc.).

Decision Table

In DMN, a Decision Table is a common way to present business knowledge in a tabular form. It has its own characteristics compared to a generic decision table.

Other Logic Types

In FlexRule, we support other types of logic as well as Decision Tables, so you can simply link this logic to business knowledge as the implementation of the logic. This logic is:

  1. Decision Table (DMN standard method)
  2. Tree (i.e. Validation, Decision)
  3. Natural Language

Decision Requirement Diagram Elements

In the table below, all of the elements on a DRD model are illustrated:

ElementNotationDescription
DecisionThe act of determining an output from a number of inputs, using decision logic which may reference one or more business knowledge models.
Business Knowledge ModelA function encapsulating business knowledge, in the form of business rules, decision tables or an analytic model. Some of the tools may not support this element. In such cases, the decision logic is directly linked to the Decision rather than the business knowledge model.
Knowledge SourceThe authority for a business knowledge model or decision.
Input DataInformation used as an input by one or more decisions. It also denotes the parameters of a Business Knowledge Model.
Information RequirementInformation – input data or decision output – required for a decision.
Knowledge RequirementThe invocation of a business knowledge model.
Authority RequirementShowing the knowledge source of an element or the dependency of a knowledge source on input data.

To add a new Decision Requirement Diagram document,

Document Types --> Business Logic --> Decision Requirement Diagram

Once you added a term, this will be the window.

DRD Properties

  1. Name: Name of the flow
  2. Variable Definition: Define variables to be used in the flow
  3. Types Definition: List of types and functions
  4. Glossaries: Link Business Glossaries and Boxed Expressions

Toolbox

The toolbox has the following items.

Complete list of commands

Check the DRD Commands for the complete list.

Top Menu

At the top menu, you can see the following items.

  1. Open the related logic document for this node: Open the logic document of a selected node
  2. Create a logic document for selected node: Create a logic document for a selected node
  3. Delete item: Delete a selected item
  4. Highlight the impacts of the selected node: Highlight the impacts of a selected node
  5. Properties: Properties of the page or a node
  6. Compile to execution plan: Shows the XML version of the diagram
  7. Business Glossary: Link Business glossaries and boxed expressions
  8. Overview of entire model: See the entire model
  9. Zooming: Zoom in or zoom out
  10. Export to image: Export the document to an image
  11. Alignments: Align nodes
  12. Resize: Resize selected nodes to a single size
  13. Layout arrangements: Automatically arrange and layout the nodes
  14. Change connections: Change connection styles to straight/ Bezier or Right Angle

Node/ Connection Properties

If you click on a node/ connection, its property window will appear. The properties vary depending on the node type.

Video Description

Sample DRD

Download the sample DRD (Sample-DRD.zip) using the attachment.

Updated on August 13, 2019

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