1. What is hierarchical interface?

What Is Hierarchical Interfaces?

• To arrange interfaces in order means hierarchical interface. It is structure in which interfaces are ranked according to levels of importance.
• In hierarchical Interfaces, one interface is a  parent’s of other interface. It means that child interface inherited External ID from its parent's interface. For example, Account interface is parent’s contact interface because of Contact inherited External ID from Account.
• Also One parent interface can have many child account but child interface has only single parent interface. eg. one Account can store many Contacts, but one Contact can’t store many Accounts.