IntegrationAdvancedpolymorphicmappingdata-model
Handle polymorphic lookups in integration mappings
Real World Scenario
Task WhoId polymorphic field breaks warehouse ETL expecting Contact foreign key only.
Expected Answer
• Split WhoId into ContactId LeadId columns in staging with type discriminator
• Integration layer resolves polymorphic to concrete type before load
• Document polymorphic fields avoided in new custom integrations
• SOQL TYPEOF for polymorphic query in Apex middleware
• Warehouse star schema optional polymorphic bridge table
• Validation rejecting ambiguous polymorphic on inbound API
Follow-Up Questions & Answers
Click to expand — each follow-up includes a direct, interview-ready answer
Direct answer: Split WhoId into ContactId LeadId columns in staging with type discriminator Also consider: Integration layer resolves polymorphic to concrete type before load In practice: Document polymorphic fields avoided in new custom integrations Optimize for scale and operational observability.
Architect Perspective
Polymorphic fields are integration kryptonite—flatten at boundary layer.