---
schema_version: "1"
id: 5c5cb5a47f6d68f068e873207503e839c9ea74220eee1dd3616ca056cf6be8d3
title: Identity Merge Scenarios
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/mktg/264-0-0/mc_pers_identity_user_profile_merging_config_scenarios.md
canonical_url: https://help.salesforce.com/s/articleView?id=mktg.mc_pers_identity_user_profile_merging_config_scenarios.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: 4d69280bca90ccd4e2cedf667b4ad4ecaad521be3ec4d20e595503a75b277c4a
description: How merging occurs depends on the identity types Personalization receives.
products:
  - Marketing
  - Salesforce Personalization
release: "264"
---
# Identity Merge Scenarios

How merging occurs depends on the identity types Personalization receives.

![Screen capture of Email Address, Customer ID, Salesforce Marketing Cloud Contact Key, and Phone identity types.](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_identity_types_1.png)

When using the Email Address, Customer ID, Salesforce Marketing Cloud Contact Key, and Phone identity types, keep the following in mind:

- This setup works best when you have a one-to-one relationship between Email Address, Customer ID, and Salesforce Marketing Cloud Contact Key.
- The Uniqueness value for Salesforce Marketing Cloud Contact Key, Email Address, and Customer ID is Identity Namespace. Each identity type value can belong to only one user profile in the dataset, so Personalization can use that value for identity lookup and user profile merging.
- The Uniqueness value for the Phone identity type is Not Unique. This identity type value can belong to multiple user profiles, so Personalization can’t use it for identity lookup or user profile merging. The same phone number can exist for multiple user profiles, so Personalization uses the Phone identity type for searches only.
- If there are multiple email addresses for a single Customer ID, Personalization stores only the most recent email address.

<table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.153110047846894%">
        <col style="width:47.84688995215311%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e66">Merge Scenario 1</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e69">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 1" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e66 ">Personalization receives an event with a single identity type. The Email
            Address identity type matches an existing user profile.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e69 ">Because the value for Email Address matches an existing user profile,
            Personalization assigns the event to that user profile.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e66 d22436e69 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_1.png" alt="Image illustrating how Personalization assigns an event based on a matched email address."></span>
          </td>

        </tr>
      </tbody>
    </table> <table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.153110047846894%">
        <col style="width:47.84688995215311%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e112">Merge Scenario 2</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e115">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 2" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e112 ">Personalization Receives an event with Salesforce Marketing Cloud contact
            key and email address identity types. The Salesforce Marketing Cloud contact
            key value matches an existing user profile, but the email address isn’t the
            same as the email address in the user profile. The email address value in the
            event has a more recent time stamp than the one in the user profile.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e115 ">Personalization assigns the event to the existing user profile using the
            Salesforce Marketing Cloud contact key, and updates the email address for the
            existing user profile to the email address in the incoming event.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e112 d22436e115 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_2.png" alt="Image illustrates Personalization assigning an event to an existing user profile using the Salesforce Marketing Cloud contact key, and updating the email address for that existing profile."></span>
          </td>

        </tr>
      </tbody>
    </table> <table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.153110047846894%">
        <col style="width:47.84688995215311%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e159">Merge Scenario 3</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e162">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 3" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e159 ">Personalization Receives an event with customer ID and email address
            identity types. The email address matches an existing user profile, but the
            customer ID in the event isn’t the same as the customer ID for that user
            profile. The customer ID value in the event has a more recent time stamp than
            the one in the user profile.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e162 ">Personalization assigns the event to the existing user profile using the
            email address, and updates the customer ID for the existing user profile to the
            customer ID from the event.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e159 d22436e162 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_3.png" alt="Image illustrating Personalization assigning an event to an existing user profile based on the email address, and updating the customer ID for the profile."></span>
          </td>

        </tr>
      </tbody>
    </table> <table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.153110047846894%">
        <col style="width:47.84688995215311%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e205">Merge Scenario 4</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e208">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 4" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e205 ">Personalization receives an event with email address and phone identity
            types. The email address value doesn’t match any existing user profiles, and
            the phone value doesn’t match any existing user profiles.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e208 ">Merging can’t occur because there aren’t any matching identifiers.
            Personalization creates a user profile using the data from the event.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e205 d22436e208 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_4.png" alt="Image illustrating how Personalization can't merge information to an existing profile because no matching identifiers exist."></span>
          </td>

        </tr>
      </tbody>
    </table> <table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.153110047846894%">
        <col style="width:47.84688995215311%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e251">Merge Scenario 5</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e254">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 5" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e251 ">Personalization receives an event with email address and customer ID
            identity types. There are two existing user profiles with identifiers that
            match the ones in the event. One profile has a matching email address and the
            other has a matching customer ID.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e254 ">Personalization merges the two existing user profiles, and then assigns the
            event data to the merged user profile.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e251 d22436e254 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_5.png" alt="Image showing two existing user profiles merging to one profile because each profile matched one received identifier."></span>
          </td>

        </tr>
      </tbody>
    </table> <table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.153110047846894%">
        <col style="width:47.84688995215311%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e297">Merge Scenario 6</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e300">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 6" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e297 ">Personalization receives an event with email address and customer ID
            identity types. There are two existing user profiles with identifiers that
            match the ones in the event. One profile has a matching email address and the
            other has a matching customer ID. However, in the user profile with the
            matching customer ID, the email address doesn’t match the email address value
            in the event.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e300 ">Personalization merges the two existing user profiles and retains the email
            address with the latest time stamp, which is the email address value in the
            incoming event.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e297 d22436e300 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_6.png" alt="Image showing two existing user profiles merging to one profile because each profile matched one received identifier."></span>
          </td>

        </tr>
      </tbody>
    </table> ![Screen shot showing the customer ID and Salesforce Marketing Cloud contact key identity types.](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_identity_types_2.png)

When using only the customer ID and Salesforce Marketing Cloud contact key identity types, keep the following in mind:

- This setup works best if there’s an internal customer key that is available for web and offline channels.
- The Uniqueness value for Salesforce Marketing Cloud contact key and customer ID is Identity Namespace. Each ID value can belong to only one user profile in the dataset, so Personalization can use that value for identity lookup and user profile merging.
- If there isn’t a one-to-one relationship with Salesforce Marketing Cloud contact key and Customer ID, Personalization retains the most recent Salesforce Marketing Cloud contact key value.

<table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.38095238095239%">
        <col style="width:47.61904761904761%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e368">Merge Scenario 1</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e371">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 1" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e368 ">Personalization receives an event that contains the customer ID identity
            type. The customer ID matches an existing user profile.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e371 ">Personalization assigns the event to that user profile.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e368 d22436e371 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_7.png" alt="Image illustrating the customer ID matching an existing user profile."></span>
          </td>

        </tr>
      </tbody>
    </table> <table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.38095238095239%">
        <col style="width:47.61904761904761%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e414">Merge Scenario 2</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e417">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario 2" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e414 ">Personalization receives an event that contains the Customer ID and
            Salesforce Marketing Cloud contact key identity types. The value for Salesforce
            Marketing Cloud contact key doesn’t match an existing user profile, but the
            value for customer ID does.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e417 ">Personalization assigns the event to the existing user profile based on the
            customer ID, and updates the Salesforce Marketing Cloud contact key value for
            that user profile.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e414 d22436e417 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_8.png" alt="Image showing the customer ID matching, but the Salesforce Marketing Contact Key not matching."></span>
          </td>

        </tr>
      </tbody>
    </table> <table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small ">
      <colgroup>
        <col style="width:52.38095238095239%">
        <col style="width:47.61904761904761%">
      </colgroup>
      <thead class="slds-text-title_caps ">
        <tr class="">
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e460">Merge Scenario</th>
          <th scope="col" class="slds-cell-wrap" style="vertical-align:top;" id="d22436e463">Resolution</th>
        </tr>
      </thead>
      <tbody>
        <tr class="">
          <td data-label="Merge Scenario" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e460 ">Personalization receives an event that contains the Customer ID and
            Salesforce Marketing Cloud contact key identity types. There are two existing
            user profiles with identifiers that match the ones in the event. One profile
            has a matching customer ID and the other has a matching Salesforce Marketing
            Cloud contact key.</td>

          <td data-label="Resolution" class="slds-cell-wrap" style="vertical-align:top;" headers="d22436e463 ">Personalization merges the two existing user profiles, and retains the
            Customer ID and the Salesforce Marketing Cloud Contact Key values with the most
            recent timestamps.</td>

        </tr>
        <tr class="">
          <td class="slds-cell-wrap" colspan="2" style="vertical-align:top;" headers="d22436e460 d22436e463 ">
            <span style="vertical-align:text-bottom;display:inline-block;"><img style="margin-bottom:0;" src="https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_personalization-264-0-0-production-enus/16bf1f60-f44c-4260-a56e-f052cfe515a3/mc_personalization/images/mc_pers_user_profile_merge_scenario_9.png" alt="Image showing two existing user profiles merging to one profile because each profile matched one received identifier."></span>
          </td>

        </tr>
      </tbody>
    </table>