---
schema_version: "1"
id: 282988d29a8c35a76b8a1c94cb9142e3a110e6bde4eb8768fab77cb1a91d67d3
title: External Lookup Relationship Fields on External Objects
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/platform/264-0-0/external_object_external_lookup_relationships.md
canonical_url: https://help.salesforce.com/s/articleView?id=platform.external_object_external_lookup_relationships.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: b496b36f1b46f22f56d2afcde64ae0adfa8ef0c1cf6504b77da6b14fbdc2d538
description: Use an external lookup relationship when the parent is an external object.
products:
  - Salesforce Platform
  - Security
release: "264"
---
# External Lookup Relationship Fields on External Objects

Use an external lookup relationship when the parent is an external object.

### Required Editions

<table class="slds-table slds-table_bordered slds-max-medium-table_stacked slds-m-bottom_small edition">
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          <td class="slds-cell-wrap" style="vertical-align:top;">Available in: both Salesforce Classic
            and Lightning Experience</td>

        </tr>
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          <td class="slds-cell-wrap" style="vertical-align:top;">
            <p>Salesforce Connect is available in: <strong>Developer</strong> Edition and for an extra
              cost in: <strong>Enterprise</strong>, <strong>Performance</strong>, and <strong>Unlimited</strong> Editions</p>
            <p><span id="external_object_external_lookup_relationships__files_connect_cloud_editions"><a name="external_object_external_lookup_relationships__files_connect_cloud_editions"><!-- --></a>Files Connect for cloud-based external data
                sources is available in: <strong>Professional</strong>, <strong>Enterprise</strong>,
                <strong>Performance</strong>, <strong>Unlimited</strong>, and <strong>Developer</strong>
                Editions</span></p>
            <p style="margin-bottom:0;">Federated Search is available in: <strong>Enterprise</strong>,
              <strong>Professional</strong>, <strong>Unlimited</strong>, and <strong>Developer</strong> Editions
            </p>
          </td>

        </tr>
      </tbody>
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An external lookup relationship links a child standard, custom, or external object to a parent external object.

The values of the standard External ID field on the parent external object are matched against the values of the external lookup relationship field. For a child external object, the values of the external lookup relationship field come from the specified External Column Name.

When you sync two external system tables with a lookup relationship field, an external lookup relationship for the mapped external objects is automatically created. This auto mapping happens only if

- The parent and child objects are synced from the same data source.
- The parent object is already synced or the parent and child objects are in the same sync operation.

![Note](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_note.png)

Note For the OData 2.0 adapter, creating an external lookup relationship is supported only in the default Olingo library and not supported in OData4J.

![Example](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_example.png)

Example

- External product catalog item (parent external object) displays a related list of support cases (child standard object).
- External customer (parent external object) displays a related list of external orders (child external object).

![Example](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_example.png)

Example For the cross-org adapter for Salesforce Connect, suppose that you store contacts and accounts in the provider org. From the subscriber org, you want to view each account’s related contacts. To do so, create an external lookup field on the subscriber org’s Contact external object. Link that external lookup field to the subscriber org’s Account external object. Then set up the page layouts for the Account external object to include a related list that displays the related Contact external object records.

![Example](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/images/icon_example.png)

Example In this screenshot, a record detail page for the Business\_Partner external object includes two related lists of child objects. This example shows how external lookup relationships and page layouts enable users to view related data from within and from outside their Salesforce org on a single page.

- Account standard object (1)
- Sales\_Order external object (2)

![External object record detail page with standard object Account related list and external object Sales\_Order related list](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-platform-extend_click-264-0-0-production-enus/5f7d9219-b7b1-4552-8891-f1aba9b289fc/extend_click/images/external_lookup_parent_detail.png)

#### See Also

- [External Object Relationships](https://help.salesforce.com/s/articleView?id=platform.external_object_relationships.htm&release=264.0.0&type=5 "External objects support standard lookup relationships, which use the 18-character Salesforce record IDs to associate related records with each other. However, data that’s stored outside your Salesforce org often doesn’t contain those record IDs. Therefore, two special types of lookup relationships are available for external objects: external lookups and indirect lookups.")
- [Create Custom Fields](https://help.salesforce.com/s/articleView?id=platform.adding_fields.htm&type=5&language=en_US)
- [Change the Data Type of a Custom Field](https://help.salesforce.com/s/articleView?id=platform.customize_fieldtype.htm&release=264.0.0&type=5 "You can modify the data type of a custom field. For example, you can change a field from Text to Text Area (Long).")
- [Considerations for Object Relationships](https://help.salesforce.com/s/articleView?id=platform.relationships_considerations.htm&release=264.0.0&type=5 "Review these considerations before creating relationships between objects.")
- [Include a Files Connect Data Source in Global Search](https://help.salesforce.com/s/articleView?id=experience.admin_files_connect_search.htm&type=5&language=en_US)