Difference between forward chaining and backward chaining.
1.It allows a computation to advance even when the value of an input or parameter property is not available.
2.Declare Expression rules and the Property-Seek-Value method work together to provide this capability.
3.The Property-Seek-Value method is the foundation of backward-chained processing.
4.Backward chaining applies to declare expressions rules with the Calculate Value field set to one of the following:
i.When used if no value present
ii.When used, if property is missing
5.For example: Area = Length x Width and is set up for backward chaining with the “Whenever used” option set on the Area property. If you try to display Area (even just in the property rule preview), the declare expression rule re-computes. This re-computation is driven by the use or referencing of Area, not by any changes in Length or Width.
Declareindex rules are instances of the Rule-declare-index classes.
Declareindex are the part of the SysAdmin category.
It will Automatically extracts the value from an embedded property when the value it has been changed.
How to refer REST service hosted in Pega (Expecting a request from an external system) from an activity (connect activity that is specified from an Assignment Service shape) ? What is the method used and what are the inputs required ?
Ask the service provider and get the end point URL....later run the wizard..If it is a secured a service make sure to sign the request with the needed keystores...later take request sample and response sample refer them while running the wizard...it will create the needed integration rule.....Call the rest service using a data page(Pega7 pattern), post processing of the data page to check if there is any exception...make sure to set a flag and conditionally handle the exception...for business exception make sure to handle after getting the result from the data page...Coming to the method---- you have to figure out which methods are supported by the service...But most commony used methods are get(request through URL) and post(encrypted body) and this request will travel on top of the HTTP protocol to hit the service..