RESTful API fails to fetch values for dblink-type fields

My pipeline fetches all records in JSON format using a Post request. Response is in {"key":"value"} format, where key indicates the field name, and value indicates the value of the field. The problem occurs with the fields with 'dblink' type. Specifically, it seems like the API is unable to retrieve the values of the fields with DBLink type and returns empty value. 

I'm wondering if there is a way to fetch the values of 'dblink' type fields?