Puzzled: connect

Sorry, folks, for a basic question, but at the moment I am absolutely puzzled and do not see anything. Scenario: SERVER is a Linux machine. There is IDS running von Computer SERVER. On Computer SERVER there is a user "databaseowner" who has got access to certain databases, tables, ... CLIENT is a Linux machine. On Computer CLIENT there is user "joe" who wants to connect to a database on SERVER via JDBC-calls. So user "joe" initiates a connect, providing "databaseowner" as user together with "databaseowner's" password. Basically, this is possible. Right or wrong? If this is possible, who has to be trusted by SERVER? User "joe" connecting from CLIENT or user "databaseowner" connecting from CLIENT? As a consequence of the above question: In this setup, is it neccessary to have a user "joe" on machine SERVER? Thanks for an answer. Norbert Heidbrink