Edit table and write changes back to DB

Question

Hi All,
I created a test program that uses AbstractTableModel to display the results of an SQL select statement in a JTable. I want to proceed to the next step which to edit cells and then write the changes back to the DB.
I imagine making a number of edits, then clicking a "save" buton and then looping through the table and checking for updated rows and then sending the sql update statements to the db.
I've spent most of this afternoon researching JTables, but am still uncertain as to where to go from here, so now I'm asking for someone to point me in the right direction.
This is where I'm at:
* I've implemented the getRowCount, getColumnCount, isCellEditable and getValueAt methods.
* My model doesn't use any vectors, or other array storage for the data, it just uses the JDBC ResultSet methods absolute(rowNumber) and getObject( colNumber)
* Whenever I edit a cell, the value reverts back to it's original. I assume this is because I havn't implemented setValueAt() yet.
In my current setup, I'm not sure how I should implement setValueAt() since all I have is the JDBC result set. Should I be implementing some kind of sparse array to hold modified data, and use that to hold updated rows? Presumably, non updated rows could still be obtained from the JDBC result set.
Anyway, I'd like to hear your advice on this.
Thanks
Iain

Answer 1

OK, here's the plan:
I already have very basic Data Access Objects (DAOs) for all of the tables in my system. Apart from encoding the most common SQL, the DAO has instance variables for each column in the table, thus implementing a record structure.
So, in my AbstractTableModel, I 'll create a Vector of the DAO, which should give me a sparse array (Vector implements a sparse array, right?) of database records that will be used to hold the rows that have been edited.
The Abstract Data Model's getValueAt( ) method would then be modified to check the cache of edited rows and get the data to display from there for updated rows, and from the ResultSet for non-edited rows.
When it's time to write updates to the database, all I have to do is process the Vector, and destroy it afterwards.
If checking the Vector each time getValueAt( ) is invoked is too expensive, then I could just implement a standard array of booleans. I'll need to keep track of rows to be inserted and deleted too, so an array of ints might be better.
This seems like a good idea to me, but I have no idea if it's gonna work....