# What constitutes the primary key for your CDP solution?

Identity Resolution

##### Post Metadata
- Posted at: over 7 years ago
- Net upvotes: 1


## Comments
### Comment 1

Tealium supports more than one unique ID, and you can declare as many as necessary. In Tealium’s system, there is not one unique or master ID, but rather the profile can hold any number of unique IDs. Many companies leverage a Company ID, a hashed Email, a Facebook ID, Rewards Program ID, and more.

Once a unique ID has been set, outside of a stitch occurring, it cannot be updated. For example, two separate profiles contain two different email addresses but are stitched together based on a different ID. In that case, the system will keep the more originally set email address in the newly created joined profile.

Additionally, an ID is added to a ‘replaced’ object in the user profile to associate the new profile to the prior separate profiles; meaning the more recently set ID is still saved! All of these IDs are available for querying via Audience Database. The reason why this is important is the concept of ‘visitor tearing,’ or breaking a visitor record apart.

##### Comment Metadata
- Posted at: over 7 years ago
- Author title: Director of Product Marketing at Tealium




## Related Product
[Tealium Customer Data Hub](https://www.g2.com/products/tealium-customer-data-hub/reviews)

## Related Category
[Customer Data Platform (CDP)](https://www.g2.com/categories/customer-data-platform-cdp)

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