Definition
An External Lookup Relationship is a special relationship field type that links a standard, custom, or external object's child records to an External Object's parent records. Unlike a standard lookup, it uses the External ID field of the External Object (rather than the Salesforce record ID) to associate records. This relationship type is essential for connecting Salesforce data to data stored outside the org, accessed in real-time via Salesforce Connect (OData, cross-org adapters, or custom Apex adapters).
Real-World Example
an architect at Skyline Consulting recently implemented External Lookup Relationship to extend their Salesforce implementation to meet growing business demands. External Lookup Relationship provides the additional capability they need without requiring a separate third-party system, keeping everything within the trusted Salesforce ecosystem and reducing integration complexity.
Why External Lookup Relationship Matters
An External Lookup Relationship is a relationship field type that links child records (on a standard, custom, or external object) to parent External Object records. Unlike a standard lookup that uses Salesforce record IDs to associate records, External Lookups use the External ID field of the External Object as the join key. This is necessary because External Objects don't have stable Salesforce IDs; their data lives in an external system and is fetched on demand.
External Lookups are essential for connecting Salesforce data to data accessed through Salesforce Connect (OData, cross-org adapters, or custom Apex adapters). For example, you might have a custom Order object in Salesforce that references customer records stored in an external ERP through an External Object. The External Lookup uses the customer's external ID to make the link, and Salesforce fetches the customer data from the ERP on demand when users view the Order. This pattern enables relational data models that span Salesforce and external systems without requiring data copying.
How Organizations Use External Lookup Relationship
- •TerraForm Tech — Uses External Lookup Relationships to link custom Salesforce records to customer master data in their ERP. The link uses the customer's external ID, and ERP data is fetched live.
- •NovaScale — Built External Lookups from custom objects in their main Salesforce org to External Objects representing data in their sister org, enabling cross-org reporting without sync.
- •CodeBridge — Combines External Lookups with Indirect Lookups depending on which side of the relationship needs to be the External Object.