Access started as local database, then allowed to put the database on a file share with locking, and later when it got ADO capabilities a general database frontend.
I assume Base is the same but then with JDBC rather than ADO as independent db API. I haven't tried Base since 2010-12, at which time my boss tried to make his own crm database. After helping him and seeing him struggle for three weeks, I just grabbed zeos and made a complete app (in Delphi) interfacing to postgress in under a week.
I still maintain that app, though since say 2018, much of these non core business app have been moved to Lazarus, so now it works under Lazarus.