Forward Chaining And Backward Chaining In PEGA

In PEGA we have 2 types of Chaining Concepts

1.Forward Chaining

2.Backward Chaining

1.Forward Chaining:

In Forward Chaining, whenever the input value changes, automatically the target value gets calculated. For Example,

Total Price = Cost * Quantity

Here, we can observe that whenever the cost or quantity changes the total prices gets calculated based on the expression used in declare expression rule.

2.Backward Chaining:

It is exactly opposite to farward chaining.There are many ways by which backward chaining gets triggered.

Total Price = Cost * Quantity

let us consider the same example that we have taken above, whenever the total price is null the declare expression checks for the input properties. (Cost & quantity).Let us consider cost is calculated as

Cost = Best Price - Discount

Now declare expression tries to get the cost value if it is null, it is like going backward & backward until it gets all the required values to calculate the target property.