Introduction to DMN

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Decision Model and Notation, or DMN, is a novel way to model business decisions. Every organization must distinguish between business decisions and business processes, not only that, they have to have a decision management practice in place.

DMN allows the capture and modeling of business decisions in a way that is easy for business people and subject matter experts to understand. It is a combination of the following models:

1. Decision Requirements Diagram – DRD
2. Decision Table
3. Boxed Expressions
4. Friendly Enough Expression Language (FEEL)

There is a big difference between modeling business decisions and business process, and DMN deliver this principle very clearly.

At a very high level, the movement of standardizing modeling and executing business decisions and rules provides a significant opportunity to all organizations for several reasons.

• Interoperability: Like all industry standards, interoperability is at the core of the benefits of supporting Decision Model and Notation (DMN). For instance, in a Business Process Management solution that can define rules but not complex decisions and business rules, you can now simply drag and drop a DMN package, and it executes the DMN model that you built in a Decision Intelligence Platform that supports the full extent of DMN to create very complex decisions and business rules.
• Migration: As the users and companies want to adopt decisioning technologies, it is easier to migrate from older systems if they support DMN. Even if the old one does not support DMN, the migration process becomes easier by capturing decisions and rules in DMN and bringing them to a new platform.
• Finding talent and training staff: Standardization makes finding talent easier, so talents who know the standard and have worked with it can be hired. Training internal staff also becomes easier because there are loads of articles, tutorials, etc., about the standard. Although the implementation of them still depends on the vendor’s capabilities, it is better than nothing.

Benefits of using DMN

1. Clarity for Stakeholders: DMN diagrams make complex decision domains easily understandable for all stakeholders.
2. Facilitated Discussions: DMN provides a natural basis for discussing and aligning on business decision scope and nature.
3. Risk Reduction: Graphical decomposition of requirements in DMN minimizes effort and risk in decision automation projects.
4. Unambiguous Business Rules: Decision tables in DMN allow a simple and reliable definition of business rules.
5. Streamlined Development: DMN specifications simplify the development of decisioning systems, with automatic validation and execution.
6. Structured Context: DMN supports developing and managing predictive analytic models within a structured context.
7. Reusable Components: DMN enables the creation of a library of reusable decision-making components.

Decision Model and Notation

DMN is a powerful modeling language and notation specifically designed to precisely define and represent business decisions and rules. Let’s see how DMN can be used to model business decisions.

DMN facilitates the modeling across three distinct levels.

1. Decision Requirements Diagram (DRD): At high level, a Decision Requirements Diagram (DRD) defines the interconnections between decisions, such as Decision Tables, reusable sub-DRDs, Business Knowledge, input data and other types of decision nodes.
2. Boxed Expressions: Boxed Expressions provides a flexible graphical notation for representing decision logic as a clear and convenient way to express business rules. These Boxed Expressions can be linked to any decision node.
3. Logic: In order to define logics, Friendly Enough Expression Language (FEEL) can be used. This can be associated with any decision node as shown in the above DRD, cell in a Decision Table, or in a Boxed Expression. FEEL is use for calculation, defining data structures, defining structured logic so on.

All of the above levels can be executed separately.