When adding an external data source to a data object, a data transform is automatically generated to map the application data model to the connector. A data transform is a rule that defines how to convert data that is in one format and class (the source) into data of another format and class (the target). A connector is a rule that defines how your application exchanges information with an external system. References: https://academy.pega.com/topic/data-records/v4 https://community.pega.com/knowledgebase/articles/data-management-and-integration/86/connectors