Duplicate detection has been around since the early versions of Dynamics CRM. In 2015, alternate keys were introduced to help identify a record based on a unique combination of attributes to perform an upsert request. An upsert is the action of inserting a record if it is new, or updating it if it already exists, based on the primary key identifier (https://msdn.microsoft.com/en-us/library/dn932135.aspx). Logically, this means whenever an alternate key is defined, any new records that are created with the same key combination will throw a duplicate exception.

This recipe will walk us though defining an alternate key for a contact, and testing the duplicate detection.