Decision Logic Verificationin DMN Decision Tables
The Decision Model and Notation (DMN) is an OMG standard for the representation of company decision logic. This tool can be used for the decision logic level verification of DMN tables. In this context, Smit et al. (2017) have recently proposed the so-called business rule management (BRM) capability framework. This framework identifies specific decision logic level verification capabilities, derived from qualitative re-search with industrial partners. Thus, the framework presented by those authors presents a comprehensive set of verification capabilities actually needed in practice. These capabilities are as follows:
- Identical rule verification. Detecting rules which have an identical input, i.e. are redundant.
- Equivalent rule verification. Detecting rules which are not identical, but still semantically equivalent. Here, our tool can verify if there exist multiple rules which use synonyms as inputs and are therefore equivalent, based on synonym relations via Wordnet.
- Subsumed rule verification. Detecting individual rules which are subsumed by other rules, i.e. they are not necessary. For example, rules containing wildcards often render more specific rules unnecessary due to subsumption.–
- Interdeterminism verification. Detecting rules which will always be activated together, but have differing or contradicting conclusions. For example, rules which will be activated together must not yield that a customer is both credit worthy, and not creditworthy, as this is logically inconsistent.
- Partial reduction verification. Checking wether ranges can be combined to simplify decision tables.
- Overlapping condition verification. Detecting whether there are any overlaps in rule conditions.
- Missing rule verification. Detecting whether there are any missing business rules, i.e. if there are rules missing for expected inputs.
Our tool implements the verification capabilities proposed by Smit et al. (2017). Please note that we did not implement "unnecessary fact verification" as this is geared towards analyzing case-dependent facts and is beyond the scope of this project. In the following, we present examples for the individual verification capabilities.
##Identical rules verification
In this table, identical rules can be identified, e.g. rules 1 and 3, or rules 4 and 5.
##Equivalent rules verification
In this table, rule 3 is subsumed by rule 4.
In this table, rule 2 subsumes rules 3-7.