Lookup Salesforce Parent Object Id using External ID

Hi CCS ,

Here are my own thoughts about your questions:

1. You need to query Salesforce to get the Contact ID based on the Contact's External ID. You can use the REST API to perform this query. Here's an example of how to do this:

GET /services/data/vXX.X/sobjects/Contact/External_ID_Field__c/External_ID_Value

Replace XX.X with your API version, External_ID_Field__c with the API name of your External ID field, and External_ID_Value with the actual External ID value.

2. The response will include the Contact ID, which you can then use in your upsert operation.

3. You have the Contact ID, you can proceed to upsert the Opportunity. Here's an example of how to do this using the REST API:

PATCH /services/data/vXX.X/sobjects/Opportunity/Opportunity_External_ID_Field__c/Opportunity_External_ID_Value
Content-Type: application/json

{
    "Name": "Opportunity Name",
    "StageName": "Prospecting",
    "CloseDate": "2025-12-31",
    "ContactId": "Contact_ID_Value"
}

Replace Opportunity_External_ID_Field__c with the API name of your Opportunity's External ID field, Opportunity_External_ID_Value with the actual External ID value, and Contact_ID_Value with the Contact ID you retrieved earlier.

Best Regards

Yilong Zhou

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