Decision tables
Decision tables derive a value that has one of a few possible outcomes, where each outcome can result from a test of a condition that includes multiple variables. A decision table lists two or more rows, and each row contains test conditions, optional actions, and a result.
Decision tables are appropriate for evaluations that include more elements compared to simple true/false evaluations. For example, you can use a decision table to estimate a car insurance payment based on the age of a driver, age of a car, and make of a car.You build decision tables by adding columns and rows. Each column represents a condition, while rows store corresponding values that the system tests at run time. For example, you can build a decision table to determine shipment costs based on the following conditions:
- The value of the order
- The weight of the parcel
- Whether the shipment is to a foreign country
Each condition is a separate column in the decision table. Additionally, every decision table includes a column that stores results that the decision table returns if all values in a row evaluate to true.
Each row includes cells that store values that the system evaluates at run time. You can insert more than one value in a cell by adding an OR condition, and then the system continues processing a row if any of the values in the cell evaluates to true.
At run time, the system evaluates the rows starting at the topmost row:
- If any condition in a row evaluates to false, processing continues with the next row. The system ignores the Return column for that row.
- If all the conditions in a row evaluate to true, the system processes the
Actions and Return columns of that row. The
next action depends on how you configure your decision table:
- To return only one result, you can configure processing to end. The system then
returns the value in the Return column as the value of the entire
rule.
In scenarios that require only one result, such as estimating delivery costs, when you end processing after receiving the first result, you improve performance and avoid unnecessary computations.
- To return multiple results, you can configure processing to continue through all
remaining rows, performing the Actions and Return calculations for any rows for which
the conditions are all true.
For example, when the decision table returns the email address of a person in a process to approve an expense, the expense might require the approval from more than one person, based on the conditions. Such scenarios require more than one result.
- To return only one result, you can configure processing to end. The system then
returns the value in the Return column as the value of the entire
rule.
- If all rows in the table evaluate to false, the system returns a default result.
Applying decision tables
You can apply decision tables in the following elements of your application:
- In a flow rule, you can reference a decision table in a decision shape .
For more information, see Adding decisions to processes.
- In an activity, you can evaluate a decision tree by using the
Property-Map-DecisionTable method.
For more information, see Creating an activity.
- A Declare Expression rule can call a decision table.
For more information, see Declare Expression rules - Completing the New or Save As form.
- A collection rule can call a decision table.
Category
Decision table rules are instances of the Rule-Declare-DecisionTable class. Decision tables are part of the Decision category.
- Creating decision tables
To better adjust to the varied factors in your business processes, you can create a decision table. Decision tables test a series of property values to match conditions, so that your application performs a specific action under conditions that you define.
- Configuring additional options for a decision table
Adjust how your decision table works by configuring additional options. For example, you can configure how a decision table behaves after one row evaluates to true, or define which elements of a decision table are available for edits.
- Specifying pages and classes of a decision table rule
To ensure that a decision table accesses or updates information on clipboard pages, specify the page name and class of the pages. At run time, these pages contain the properties that a decision table references on other tabs of its rule form.
- More about Decision Tables
Use a decision table to derive a value that has one of a few possible outcomes, where each outcome can be detected by a test condition. A decision table lists two or more rows, each containing test conditions, optional actions, and a result.
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