Are you asking about how to update the changed values in Database? If you display all the records from the DB table and allow the user to edit anyone including the primary key of the table then it will be difficult to update the record in the table. If there is a situation that
you should allow all the values to updated by user then define a serial no of any number in table which will not be changed and every record will be updated against that serial no column. Your table would be something like following
SerialNO Col1 Col2 Col3
1 val val val
2 val val val
Now every record is against a spcific unique serial no so you can use that no while updating the records. I don't know JTable but you can store this serial no against each record in any hidden field or something else.
If i misunderstood the problem then expalin.