Forum Post: RE: How "AccountId" is filled from webapi/soap endpoint perspective on Contact entity ?

Hello Clément, On the Contact entity the field 'accountid' is a virtual field, it doesn't actually exist. (Only in the WebApi this field is refered to as '_accountid_value' due to the OData implementation, the actual name of the field is just 'accountid' and yes, it exists in some DB views but, it doesn't exist in a table) The field 'parentcustomerid' is a real lookup field and has a little Dynamics 365 specific quirk: you can enter both the ID for an Account, as well as a Contact -- The field 'accountid' is a virtual one, which is supposed to only contain a GUID value when 'parentcustomerid' is set to the GUID of an Account record, otherwise it will be NULL Likewise, there is also a virtual field called 'contactid', this one will only contain a GUID value when 'parentcustomerid' is set to the GUID of a Contact record, otherwise it will be NULL. -- To specifically answer your question: The '_accountid_value' field is not filled via background job, nor is there any cache, it is possible that it is NULL because the value for 'parentcustomerid' was NOT set to an Account record. Perhaps the value for 'parentcustomerid' is accidentally set to a a record that doesn't exist?