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This document describes how the decision graph is stored in such a way that it follows the XSD of the Decision Model and Notation (DMN) specification.
The goal of storing a decision is that an organization can rebuild a model of the decisions that have been made by the runtime. By rebuilding the decisions with the actual values, organization have insight how decisions are made. The meta model for the exchange of decisions according to the DMN specifications prescribes that each decision, each business knowledge model and each input variable is a separate DMN element. We will show how this works in practice with an example.
More information on the specification of the meta model and the XSD can be found here: http://www.omg.org/spec/DMN/1.0/Beta1/
Description of all the parts of a Decision Rule Graph (DRG) at runtime
XML representation
In the example decision requirements graph (DRG) shown above, the decision was made on the amount of a monthly installment. When storing this decision in the trace engine, an XML representation of that decision is generated. The XML document contains the entire DRG from the image shown above. All the XML components for a single DRG are placed between the definitions
start and end tag.
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<?xml version="1.0" encoding="UTF-8"?> <Definitions xmlns="http://www.omg.org/spec/DMN/20130901" xmlns:bq="http://www.blueriq.com/dmn/drg" id="DRG_for_Application.RequiredMonthlyInstallment" namespace="http://www.blueriq.com/dmn"> <Decision id="decision1" name="Application.RequiredMonthlyInstallment"> <bq:value>284.219374515558</bq:value> <bq:instanceId>e2575ae5-e344-46bd-88b5-f5a98cb76ca8</bq:instanceId> <bq:sourceType>Default</bq:sourceType> <bq:justificationText justificationTextId="RequiredMonthlyInstallmentCalculation"> The formula is M = P * (J / (1 - (1 - (1 + J)^ -N)) - F. M: monthly payment. P: principal or amount of loan. J: monthly interest; annual interest divided by 100, then divided by 12. N: number of months of amortization, determined by length in years of loan. F: monthly fee. </bq:justificationText> <informationRequirement> <InformationItem id="decision1InformationItem0" name="RequestedProduct.Amount" /> <requiredInput>inputData1</requiredInput> </informationRequirement> <informationRequirement> <InformationItem id="decision1InformationItem1" name="Control.MonthlyInterest" /> <requiredDecision>decision2</requiredDecision> </informationRequirement> <informationRequirement> <InformationItem id="decision1InformationItem2" name="RequestedProduct.Term" /> <requiredInput>inputData3</requiredInput> </informationRequirement> <informationRequirement> <InformationItem id="decision1InformationItem3" name="RequestedProduct.MonthlyFee" /> <requiredDecision>decision3</requiredDecision> </informationRequirement> <knowledgeRequirement> <requiredKnowledge>businessKnowledgeModel3</requiredKnowledge> </knowledgeRequirement> </Decision> <Decision id="decision2" name="Control.MonthlyInterest"> <bq:value>0.0050</bq:value> <bq:instanceId>7e72ae81-34a8-4c52-8538-0e09549ab3fe</bq:instanceId> <bq:sourceType>Default</bq:sourceType> <informationRequirement> <InformationItem id="decision2InformationItem0" name="RequestedProduct.Rate" /> <requiredInput>inputData2</requiredInput> </informationRequirement> <knowledgeRequirement> <requiredKnowledge>businessKnowledgeModel1</requiredKnowledge> </knowledgeRequirement> </Decision> <Decision id="decision3" name="RequestedProduct.MonthlyFee"> <bq:value>20.0</bq:value> <bq:instanceId>e7b51f3c-0181-42b9-94f3-dd6fc05ddae3</bq:instanceId> <bq:sourceType>System</bq:sourceType> <informationRequirement> <InformationItem id="decision3InformationItem0" name="RequestedProduct.ProductType" /> <requiredInput>inputData4</requiredInput> </informationRequirement> <knowledgeRequirement> <requiredKnowledge>businessKnowledgeModel2</requiredKnowledge> </knowledgeRequirement> </Decision> <InputData id="inputData1" name="RequestedProduct.Amount"> <bq:value>10000.0</bq:value> <bq:instanceId>e7b51f3c-0181-42b9-94f3-dd6fc05ddae3</bq:instanceId> <bq:sourceType>User</bq:sourceType> </InputData> <InputData id="inputData2" name="RequestedProduct.Rate"> <bq:value>6.0</bq:value> <bq:instanceId>e7b51f3c-0181-42b9-94f3-dd6fc05ddae3</bq:instanceId> <bq:sourceType>User</bq:sourceType> </InputData> <InputData id="inputData3" name="RequestedProduct.Term"> <bq:value>36.0</bq:value> <bq:instanceId>e7b51f3c-0181-42b9-94f3-dd6fc05ddae3</bq:instanceId> <bq:sourceType>User</bq:sourceType> </InputData> <InputData id="inputData4" name="RequestedProduct.ProductType"> <bq:value>Standard loan</bq:value> <bq:instanceId>e7b51f3c-0181-42b9-94f3-dd6fc05ddae3</bq:instanceId> <bq:sourceType>User</bq:sourceType> </InputData> <BusinessKnowledgeModel id="businessKnowledgeModel1" name="Control.MonthlyInterest-default-expression" /> <BusinessKnowledgeModel id="businessKnowledgeModel2" name="DecisionTableMonthlyFee" /> <BusinessKnowledgeModel id="businessKnowledgeModel3" name="Application.RequiredMonthlyInstallment-default-expression" /> </Definitions> |
XML representation of the decision requirements graph shown above.
Decision
Between the decision
tags, the DRG components are placed to identify and determine the decision. The attribute name
of the decision refers to an [entity.attribute] that was subject to a decision. The id
attribute uniquely identifies the decision in the entire diagram. Inside the decision other default and custom XML components are included. The custom components can be identified by the bq
prefix. The value
element contains the value after determination of the decision. To determine a decision, information is needed. To accomplish this, informationRequirement
tags are included inside a decision. These tags point on their way forth to input data (inputData
) or other decisions (decision
).
...
When an attribute contains a justification text, it will also be displayed inside the DRG graph and the XML variant. In XML this text is displayed between the JustificationText
start and end tags inside a decision.
Business knowledge model
Inside the name
attribute of the BusinessKnowledeModel
the name of a logic component, such as a decision table, default rule, business rule is placed.
...