Creating connection c = DriverManager.getConnection ("jdbc:postgresql://localhost:5432/postgres",             "postgres", "postgre_manas9"); Statement : executes static sql queries need to use CreateStatement()  on an active connection object st = con.createStatement(); st.execute(): : use when you are not sure that query would return data or manipulate data executeQuery(): returns a  ResultSet executeUpdate() : used in transaction, delete and update operations Prepared Statement : execute precompiled queries to improve performance. PreparedStatement object accepts parameters at runtime.