Ledger Journal trans update

Hi all,

I have an requirement like i need to have update button in the General journal -->lines .where after uploading the entries from excel,there has to be something updated like for tat particular voucher when the project is selected the offset account text value need to be updated in ledgerjournaltrans_project table as the category id.I can write a method in clicked event of the update button.But that update has to be done only for that journal which i entered into.It should not update all the journal lines…its has to updated only the journal number of the selected line in the ledgerjournal trans table