Show all document names.
select document_name from all_documents
Also show their location name.
select t1.document_name, t3.location_name from all_documents as t1 join document_locations as t2 on t1.document_id = t2.document_id join ref_locations as t3 on t2.location_code = t3.location_code
What is the location for the document titled "Robin CV"?
select t3.location_name from all_documents as t1 join document_locations as t2 on t1.document_id = t2.document_id join ref_locations as t3 on t2.location_code = t3.location_code where t1.document_name = "Robin CV"