So you got two thigns to do on submit event.
1. load to database
2. Write/update XML file
For writing to a table. You can use
jdbc api to to connect and use any database, A good tutorial is
available here.
For writing/updating xml.
I can think of two options now.
1.Read the database table and create an xml file using simple File IO
2.Create an XML, and edit/modify/remove them using DOM api.
IBM has a basic tutorial on understanding DOM Having a schema is is always better for future applicaiton upgrades and maintainability, data
exchange and presentations etc., BUT not really necessary.