Java Design Pattern on saving form data

I have a jsp page having many sections/categories to fill hardware configuration details and each section/category has many details to be filled in either by selecting a value in a list box or entering data in a text box. The user may fill in some fields of some section and can choose to fill other sections later. When user logs in next time to fill data, he must be shown the previously filled in data for respective sections/categories. The current design is, when user is entering any data and goes to next field, an ajax call is made to persist the entered data in DB. So if there are 10 fields in a section and if there are 10 sections in the form, 100 JDBC calls are made and if user wants to edit already entered field, additional JDBC calls are being made. Also the 10 fields in a section are dependent on each other, for example if the first field is “Operating System Name” and if I select as “Windows” then the next field “OS Version” should only show values “2000,2007 2008 etc” and the next field “OS Architecture” should only show relevant values for Windows and its Version. This was the main reason why a JDBC call is made each time when user enters a value in a field

Need your advice on this design to make minimal JDBC calls and the current design more efficient. Thanks