Dmn

DMN Demystified, Part 3. Key Element 2: Decision Table

A second key feature supported by every DMN tool is the decision table. In DMN, decision tables are one form of expression used to determine the value of a decision or BKM. Decision tables have been around for 40 years, but DMN defines specific formats and rules for their construction. In one common format, the columns of the table represent inputs and outputs, and the rows represent decision rules. The combination of an input column heading, called input expression, and an input table cell, called input entry, defines a Boolean expression.

By: Bruce Silver December 29, 2016 dmn Read More

DMN Demystified, Part 4. Key Element 3: FEEL

If DMN just wanted to be a requirements-gathering notation along the lines of BPMN 1.x, DRDs and decision tables would be enough. (And unfortunately, to many decision management vendors and consultants, those are enough!) But DMN has higher aspirations. Like BPMN 2.0, it seeks to unify modeling and execution in a single language, accessible to business people but powerful enough to handle real-world decision logic. In the end, DMN had to invent that language, called FEEL.

By: Bruce Silver December 29, 2016 dmn Read More

DMN Demystified, Part 5. Key Element 4: Boxed Expressions

Last time I mentioned that FEEL is just an expression language not a programming language. It does not have statements. It cannot create variables. But, of course, you need those to define executable decision logic! So where do they come from? What makes DMN business-friendly is that variables and their value expressions are created graphically, in diagrams and tables. We've already seen how each decision node in the DRD defines a variable of the same name, and how a decision table provides its value.

By: Bruce Silver December 29, 2016 dmn Read More

DMN Demystified, Part 6. Key Element 5: Metamodel and Schema

All of the conceptual elements of DMN - their names, attributes, relationships to each other, whether they are required or optional, and so forth - are formally defined in the specification by a metamodel, a set of UML class diagrams. Here, for example, is the metamodel for a Decision: Closely related to the metamodel is the XML Schema, or XSD, defining the standard XML interchange format for DMN models. Here is the XSD for decision table inputs: The metamodel and schema define the internal plumbing of DMN.

By: Bruce Silver December 29, 2016 dmn Read More

DMN Demystified, Part 7. Conformance Levels

While unifying decision modeling and execution is a laudable goal, OMG realizes not all DMN vendors and practitioners want to do that. So DMN defines three levels of conformance to the standard. A tool vendor can implement just a sliver of DMN and still proudly slap that "standards-based" label on their software. Conformance Level 1 (CL1) applies to tools that support DRDs and non-executable decision tables. Non-executable means the decision logic may be defined informally, in natural language, for example, and makes no presumption of completeness, consistency, or even common sense.

By: Bruce Silver December 29, 2016 dmn Read More

DMN Demystified, Part 8. What's Not in DMN 1.1

DMN 1.1 is the first implementable version of the standard. The spec is done, but won't be released to the public until mid-2016. A lot of work went into it, so people are surprised at all the things that are not in it: Business glossary. Howls of anguish went out online when it was revealed that DMN would not specify a Business glossary, a business-maintained data dictionary for decision models. Actually, all of the elements that go into the glossary - the element's name, description, datatype, allowed values, etc.

By: Bruce Silver December 29, 2016 dmn Read More

Announcing DMN Method and Style Basics - Training and Certification

I am happy to announce a brand new class, DMN Method and Style Basics, based on the Trisotech DMN Modeler, tailored for business users. The training includes 60-day use of the Trisotech Digital Enterprise Suite and post-class certification. Click here to register. Until October 31, we are offering it for the special price of $295, after which the price will revert to the standard price of $695. By the end of the year, I plan to add a follow-on DMN Method and Style Advanced class, for more technical decision modelers.

By: Bruce Silver December 29, 2016 dmn Read More

DMN Business Knowledge Models - Love 'em or Hate 'em?

If you're like most people trying to find out about DMN by reading the spec, you focus on the diagrams and examples. And you probably come away thinking, Yikes, what a mess! The thing that elicits this response from most people is the proliferation of business knowledge models (BKMs), those rectangles with clipped corners that seem to be stuffed in every nook and cranny of the DRD. But here's the thing: Unless you want to expose that bit of decision logic for reuse, BKMs are unnecessary.

By: Bruce Silver December 29, 2016 dmn Read More

DMN Method and Style - New Book and Training Now Available

I've been heads-down for a while working on a new book and training: DMN Method and Style. The Decision Modeling and Notation standard now promises to transform the world of proprietary decision management software in the same way that BPMN upended the world of workflow, EAI, and business process analysis software a decade ago. Do we even use those terms any more?? DMN is a business-oriented graphical language that is both descriptive and executable.

By: Bruce Silver December 29, 2016 dmn Read More

DMN on the Rise at bpmNEXT

bpmNEXT 2016 just concluded its fourth event this week in Santa Barbara, and it was even better than ever! One highlight for me was the rapid pace of progress in DMN implementation. Before this event I was beginning to despair that tool vendors would implement only the barest outlines of DMN, nothing that could fulfill the promise of a business-friendly, model-based, executable, tool-independent decision language. Instead I come away energized and excited!

By: Bruce Silver December 29, 2016 dmn Read More