Manage

The manage step provides data management functionality for your application and/or process.

Below is the code for Manage():

   //

   // Manage()

   //

   // This function performs record adds and updates using locking

   //

   private static void Manage ()

   {

      System.out.println("MANAGE");

      // delete any existing records

      Delete_Records();

      // populate the table with data

      Add_CustomerMaster_Records();

      // display contents of table

      Display_Records();

      // update a record under locking control

      Update_CustomerMaster_Record();

      // display again after update and effects of lock

      Display_Records();

   }

   //

   // Delete_Records()

   //

   // This function deletes all the records in the table

   //

   private static void Delete_Records ()

   {

      System.out.println("\tDelete records...");

      try

      {

         stmt.executeUpdate("DELETE FROM custmast");

      }

      catch (SQLException e)

      {

         Handle_Exception(e);

      }

      try

      {

         conn.commit();

      }

      catch (SQLException e)

      {

         Handle_Exception(e);

      }

   }

   //

   // Add_CustomerMaster_Records()

   //

   // This function adds records to table CustomerMaster from an

   // array of strings

   //

   private static void Add_CustomerMaster_Records ()

   {

      System.out.println("\tAdd records...");

      String data[] = {

         "('1000','92867','CA','1','Bryan Williams','2999 Regency','Orange')",

         "('1001','61434','CT','1','Michael Jordan','13 Main','Harford')",

         "('1002','73677','GA','1','Joshua Brown','4356 Cambridge','Atlanta')",

         "('1003','10034','MO','1','Keyon Dooling','19771 Park Avenue','Columbia')"

      };

      try

      {

         // add one record at time to table

         for (int i = 0; i < data.length; i++) {

            stmt.executeUpdate("INSERT INTO custmast VALUES " + data[i]);

         }

      }

      catch (SQLException e)

      {

         Handle_Exception(e);

      }

      try

      {

         conn.commit();

      }

      catch (SQLException e)

      {

         Handle_Exception(e);

      }

   }

   //

   // Display_Records()

   //

   // This function displays the contents of a table.

   //

   private static void Display_Records ()

   {

      System.out.print("\tDisplay records...");

      try

      {

         // execute a query statement

         ResultSet rs = stmt.executeQuery ("SELECT * FROM custmast");

         // fetch and display each individual record

         while (rs.next()) {

            System.out.println("\n\t\t" + rs.getString(1) + "   " + rs.getString(5));

         }

         rs.close();

      }

      catch (SQLException e)

      {

         Handle_Exception(e);

      }

   }

   //

   // Update_CustomerMaster_Records()

   //

   // Update one record under locking control to demonstrate the effects

   // of locking

   //

   private static void Update_CustomerMaster_Record()

   {

      System.out.println("\tUpdate record...");

      try

      {

         stmt.executeUpdate("UPDATE custmast SET cm_custname = 'KEYON DOOLING' where cm_custnumb = '1003'");

         System.out.println("\tPress <ENTER> key to unlock");

         System.in.read();

         conn.commit();

      }

      catch (SQLException e)

      {

         Handle_Exception(e);

      }

      catch (Exception e)

      {

         Handle_Exception(e);

      }

   }