The reference for the key name of the fields map.
The types of keys that a ProfileObject can have. Each ProfileObject can have only 1 UNIQUE key but multiple PROFILE keys. PROFILE, ASSET, CASE, or ORDER means that this key can be used to tie an object to a PROFILE, ASSET, CASE, or ORDER respectively. UNIQUE means that it can be used to uniquely identify an object. If a key a is marked as SECONDARY, it will be used to search for profiles after all other PROFILE keys have been searched. A LOOKUP_ONLY key is only used to match a profile but is not persisted to be used for searching of the profile. A NEW_ONLY key is only used if the profile does not already exist before the object is ingested, otherwise it is only used for matching objects to profiles.
An object that defines the Key element of a ProfileObject. A Key is a special element that can be used to search for a customer profile.