hi,
first,
you should read about
JDBC:
http://java.sun.com/docs/books/tutorial/jdbc/ This is the pure
Java Driver that connects your app to the database. It allows you to send SQL-Queries to the database and to retrieve objects that wrap the results.
What you do with the results is a design decision. What I can tell you from experience is: do not mix up JDBC code with Swing code. Rather build data classes you can hand around in your code. It's similar to the model-view separation in JTable and TableModel. Thus, the database can change, but you don't have to mess with your Swing classes.
regards
Chantal