Difference between Primary Identity and Identity

[Michael_Soprano]

Is there any practical difference in AEP? I know that Primary Identity has to be filled but are there any differences between those two? Things to be to careful about?

[bjoern__koth]

Think of it like a database. The primary identity is the Primary Key of your database row.

The supporting identities are similar to Foreign Keys that help join to other rows.

Primary identities are the "main" identifier when the record is stored. They serve as main profile stitching anchor.

Secondary or Additional Identities are not the primary identifier and optional, but still used for stitching profiles together.

Per record / event, multiple identites are allowed, and they still participate in the identity graph for cross-device/-channel stitching.

All identities (primary + supporting) participate in:

• Identity Graph stitching
• Profile merging
• Cross-device/channel linkage

Bottom line, both types link profiles together, but primary identity is the "official" key for that specific record.

The choice matters more for data organization than for stitching capability.

[Karuppiah_Sakthivel]

Bjoern is correct that both types stitch profiles together in the Identity Graph, there are three critical practical differences you must be careful about:

1. A Profile-enabled schema must have exactly one Primary Identity. Without it, the record cannot be stored in the Real-Time Customer Profile.
2. When a GDPR/CCPA request is processed, AEP uses the Primary Identity to locate and delete fragments. If you incorrectly label an ID as secondary, a privacy request for that ID might not fully wipe the associated data.
3. The Primary Identity is the "folder name" for that specific data fragment. While secondary IDs help link profiles, the Primary ID is what AEP uses to index and retrieve that specific record in the Profile Store.

Use the Primary Identity for the ID that "owns" the record (like a CRM ID for a customer record), and use Secondary Identities for other IDs that just happen to be present (like an Email or Phone number).