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Working with Decision Trees
 
About Decision Tree Processing Modes
Accessing the Decision Tree Wizard
Creating a Decision Tree
Modifying a Decision Tree
A decision tree is a decision entity. It uses a tree-like structure to depict a complex set of rules in a IF Condition THEN Result syntax.
Decision Tree Structure
A decision tree consists of nodes and links. A node can represent the root, a condition (blue color), an assignment result and its assigned result value (green color), or an action result and its action status (green color). A link can be a root link or a condition link. A root node can be linked to one or more condition nodes, and a condition node can be linked to one or more condition nodes or result nodes.
The following table gives an overview of the decision tree elements and their graphical representation:
Element Name
Graphical Representation
Description
Root Node
The root node is the root of the decision tree. All decision branches start from here.
Root Link
A root link connects the root node with a condition node on the first level. A root link represents an unconditional branch to a condition node and is not evaluated.
Condition
A condition node contains a reference to one input or input/output parameter element. Condition links can branch off of this node.
Condition Link
Three types of condition links exist:
*Condition link that contains an operator and a condition value. It represents a conditional branch to the element on the right side of the condition line when the condition evaluates to true.
*Condition link that is left empty. It represents an unconditional branch and is not evaluated. Tree evaluation continues with the successor node, if there is any.
*Otherwise condition link. It contains the otherwise operator and a condition value, and it represents the last branch of a condition node. Its path is taken if none of the previous branches from the parent condition evaluate to true.
The following types of condition values exist:
*Literal value.
*Value range.
*Parameter element (marked by a dotted line).
*Action that delivers an output value (marked by a dotted line and () behind the action name).
*Constant (marked by a dotted line).
*Expression.
Assignment Result Node
An assignment result node contains a reference to one output or input/output parameter element, an operator and the assigned result value. The followign types of result values exist:
*Literal value.
*Value range.
*List.
*Parameter element (marked by a dotted line).
*Action that delivers an output value (marked by a dotted line and () behind the action name).
*Constant (marked by a dotted line).
*Expression.
Assignment result nodes can be chained together along with action result nodes.
Action Result Node
An action result node contains a reference to the action that is to be invoked and one of the following action statuses:
* (action is enabled).
* (action is disabled).
Mapping can be specified. Action result nodes can be chained together along with assignment result nodes.
Example
The following rules can be modeled in a decision tree:
Rule 1:
IF a customer has customer status silver, THEN this customer gets a discount of 10%.
Rule 2:
IF a customer has customer status gold, THEN this customer gets a discount of 20%.
The decision tree uses one condition node with two condition values, and two assignment result nodes:
This decision tree corresponds to the following decision table:
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