Declarative Rules

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·         Declarative           =          Automatic

·         Declarative rules can be created under decision category.

·         These are created and applied on properties.

·         Where ever we use the properties (which involves in the declarative rule) throughout our application, declarative rules will be automatically called and executed.

·         There are different types of declarative rules available.

1)      Declare Expression

2)      Declare Constraint

3)      Declare On change

4)      Declare Trigger

5)      Declare Index

·         Declare Expression: - Declare Expression rule is used to perform automatic calculations.

·         Whenever input properties are changing the target property value gets automatically updated. This is called “Forward Chaining”.

·         @DateTime.addToDate(.TransactionDetails.TransactionEffData,364,0,0,0)

·         Example: Product              Unit Price        Quantity          Price

                                   Pro1                5                      5                      25

Declare Constraint

·         A constraint validates one property value against another property

·         Every time we use the property, it automatically calls the constraint and validates. This happens throughout the application

Declare On Change

·         Declare on change rule gets automatically executed whenever there is a change in the property value

·         It looks for the property changes, which we have used in the on change rule

·         When this rule gets executed, it executes an activity based on the condition satisfied

·         The activity which we are going to call from Declare on change rule must be of type ‘On Change’

Declare Trigger

·         A declare trigger rule is an instance of class Rule-Declare-Trigger

·         A trigger rule gets fired when an instance of trigger class is saved, updated, deleted

·         Trigger rule will be associated with

o   A when condition

o   An activity

·         Whenever an instance is saved, updated or deleted, declare trigger gets fired automatically and which executes the associated activity based on the condition satisfied.

·         The activity should be of type ‘Trigger’

·         Declare trigger should be created under table class which we want to monitor for its changes.