A decision table groups rules that have similar conditions and actions, and helps you spot problems such as overlaps and gaps among the rules.
A decision table contains rows and columns that work together to form rules. In the following table, each numbered row expresses a rule. The columns define the conditions (Grade and Amount of loan) and actions (Insurance required and Insurance rate) of the rules in the table.
| Grade | Amount of loan | Insurance required | Insurance rate | ||
|---|---|---|---|---|---|
| Min | Max | ||||
| 1 | A | <100,000 | false | ||
| 2 | 100,000 | 300,000 | true | 0.001 | |
| 3 | 300,000 | 600,000 | true | 0.003 | |
| 4 | ≥600,000 | true | 0.005 | ||
| 5 | B | <100,000 | false | ||
| 6 | 100,000 | 300,000 | true | 0.0025 | |
| 7 | 300,000 | 600,000 | true | 0.005 | |
| 8 | ≥600,000 | true | 0.0075 | ||
When an application calls a decision table, the action rules are executed. If the conditions in a row are met, the rule that is formed by the row performs the actions in the row.
You can add rows to the decision table and enter values in their cells to create new rules. You can also define preconditions that apply to all the rules in a table. Error markers help you find overlaps and gaps in your rules.