DECLARE Trigger Rules establish the relationships between events in your case types. Declare Trigger rules, which conduct activities in response to a case's specified event. As a result, you're able to develop adaptable apps that PROPERLY fit your company's requirements. When your application creates, changes, or deletes a class in the database, declare Trigger rules to start actions. Actions in a case, such as storing a case or modifying information in a case, are related to operations on classes. Declare Trigger rules can also be used to track property changes and for auditing.

Following steps must be followed to create a declare trigger in PEGA :

1. Click Create Decision Declare Trigger in Dev Studio's header.
2. Provide a descriptive name for the rule you want to establish in the Label area.
3. Indicate where your application SAVES the rule in the Context section:
   1. Select an application to store the rule from the list of application layers.
   2. Enter the class to which the rule applies in the Apply to field. Property values in this class and classes that inherit from it are monitored by the system at runtime.
   3. Select a rule-set and a rule-set version to store the rule in the Add to rule-set list.
4. Click on Create and Open.
5. Select a type of event to trigger the rule in the Trigger when an instance is list on the Triggers tab:
6. In the Condition section, in the When box, enter a When condition rule to run the rule only when a case fulfill given circumstances. The system checks the conditions at runtime and only EXECUTES the Declare Trigger rule if the When condition is true.
7. Enter the activity that the rule initiates in the Name field of the Trigger activity section.
8. Determine how the action will run in the Execute list.
9. Click on Save and the Declare Trigger would be created.