Salesforce Facts by Abhishek

We can make use of ContactId field in User object to identify if the current logged in user is a community user or not. The same can be used in LWC. Attached is the screenshot. Note: The ContactId field cannot be updated manually and while trying to do so, the below error is encountered: 'You can't create a contact for this user because the org doesn't have the necessary permissions. Contact Salesforce Customer Support for help.'

The ContactId field on opportunity is a read-only field and it is not visible in the page layout. This field can be updated only using the IsPrimary flag of the Opportunity Contact Role. Reference:  https://developer.salesforce.com/docs/atlas.en-us.object_reference.meta/object_reference/sforce_api_objects_opportunity.htm