error updating the database

I am creating a library management system using visual c# and Ms Access.
I am able to search entries from the database but i am unable to add,,delete,or update entries fromt he database.In short i am unable to modify the database.
I am trying to modify the database like this

I have used OleDbConnection,OleDbCommand objects to do this, i used jet 4.0 as provider.It is not giving any error though the database is nt getting modified , when i digged a lil deep and saw the bin folder of my project then i was schocked to see that there was a copy of my database (.mdb) ther and all the changes have been applied to it.But when i run the program once again it s copying the orginal database again into the bin folder so the changes are nt evident ,
suggest some solution to this....