well thanks my original problem is solved, but

one question with respect to
one more thing:Its not a good idea to open a connection at the form load and closing the connection at the form closing

for more security to the database,just open the connection,perform executenonquery and then close the connection immediately
well if say every minute i want to get some data from the db, then should i connect and disconnect from the db every minute.

i also had an doubt on the same topic

If i have around 20 to 30 form which will access the same db , then do i need to create the connection object in each and every form