Updating values is a feature of DE. Right-click on a table and select Edit Table Rows and away you go…and of course, doing an UPDATE table SET … from the SQL Editor is just fine too.
To do the Direct Table Edit, you do have to have a JDBC driver that supports RowSets and ResultSet.TYPE_SCROLL_SENSITIVE and ResultSet.CONCUR_UPDATABLE – JDBC 2.0 features. You will need to check your JDBC driver documentation to figure out if it is supported.