Why do we use External Mapping in a class rule?
@TanyaS58 please check the below link
https://docs-previous.pega.com/application-development/85/external-mapping-tab-class-form.
In brief, it is used for column to column mapping. For eg:- if we integrated with external db, then we need to map external DB column to pega property.
Lets say a class is mapped to the db table. If we want to map the db column with the property then we can use this option.
@P.Siva.Praveen if the class is already mapped to the db so that means all the properties present in our class will be a column in that db so why will we need external mapping ?
@Anoop Krishna but i have a slight confusion here ,we already have one option to map external database table with our class properties by following Configure>datamodel>classes& properties>Database class mappings. So are these options similar to each other?
@TanyaS58 ya you are right, by running that wizard a class in pega will be created which refers to external DB. But we need a mapping somewhere to map external DB column to pega property. That is done in this tab.
@TanyaS58 If we have a table whose column name is different than the propertyname in Pega .. we can use this tab to map.