Writable External Objects Considerations for Salesforce Connect OData Adapters

• An external object custom field associated with an OData complex type on the external system is always read only, even if the external object is writable.
• Writable external objects aren’t available for high-data-volume external data sources.
• If your external system requires write operations to specify values for entity keys, ensure that External ID standard field values and entity key values don’t contradict each other. For each write operation, include either the External ID standard field value or the custom field values that form the entity key, but never both.
• When an external object record is edited, Salesforce Connect sends an HTTP request to the external system.
  • If the record is edited from the Salesforce user interface, the HTTP request includes all fields, including the fields that weren’t changed.
  • If the record is edited from the API, only the specified fields are included in the HTTP request.
• Make sure that the OData producer supports the HTTP methods that are used by your Salesforce Connect adapter.

  To Do This	OData 4.01 Adapter Uses This HTTP Method	OData 4.0 Adapter Uses This HTTP Method	OData 2.0 Adapter Uses This HTTP Method
  Create record	POST	POST	POST
  Edit record	PATCH	POST with X-HTTP-METHOD header set to PATCH	POST with X-HTTP-METHOD header set to MERGE
  Delete record	DELETE	DELETE	DELETE
  View record	GET	GET	GET

Also review the considerations that apply to all Salesforce Connect adapters.