transexample.java

这是一本描述JDBC数据库的书籍

/*
 * TransExample.java
 *
 * Created on June 12, 2005, 10:56 PM
 *
 * To change this template, choose Tools | Options and locate the template under
 * the Source Creation and Management node. Right-click the template and choose
 * Open. You can then make changes to the template in the Source Editor.
 */

package ch03;

import java.sql.*;
import javax.sql.*;
import java.io.*;
import common.*;
/**
 *
 * @author kevin
 */
public class TransExample {
    
   public static void main(String [] args)
  throws Exception{



    // create a Connection object named rcConnection
    Connection rcConnection = ConnectionFactory.getConnectionFactory().getConnection();
    
    rcConnection.setAutoCommit(false);

    // create a Connection object named serConnection
    Connection serConnection = ConnectionFactory.getConnectionFactory().getConnection();
    serConnection.setAutoCommit(false);

    // set transaction isolation level to TRANSACTION_SERIALIZABLE
    // for serConnection - serConnection will no longer see
    // phantom rows, non-repeatable reads or dirty reads
    System.out.println("Setting transaction isolation level to " +
      "TRANSACTION_SERIALIZABLE for serConnection");
    serConnection.setTransactionIsolation(
      oracle.jdbc.OracleConnection.TRANSACTION_SERIALIZABLE
    );

    // create two Statement objects, named rcStatement and
    // serStatement
    Statement rcStatement = rcConnection.createStatement();
    Statement serStatement = serConnection.createStatement();

    // display all products using rcStatement
    System.out.println("List of products using rcStatement");
    displayProducts(rcStatement);

    // display all products using serStatement
    System.out.println("List of products using serStatement");
    displayProducts(serStatement);

    // add product #6 using rcStatement
    System.out.println("Adding product #13 " +
      "using rcStatement");
    rcStatement.executeUpdate(
      "INSERT INTO simple_tbl " +
      "(id, name) VALUES " +
      "(13, 'JDBC Programming')"
    );

    // update product #1 using rcStatement
    System.out.println("Updating product #1's name to New Science " +
      "using rcStatement");
    rcStatement.executeUpdate(
      "UPDATE simple_tbl " +
      "SET name = 'New Science' " +
      "WHERE id = 1"
    );

    // commit the changes using rcConnection
    System.out.println("Committing changes using rcConnection");
    rcConnection.commit();

    // display all products using rcStatement
    System.out.println("List of products using rcStatement");
    displayProducts(rcStatement);

    // display all products using serStatement -
    // the new product (a phantom row) and the
    // modified product name (a non-repeatable read) 
    // are not visible to serStatement because it has a transaction
    // isolation level of TRANSACTION_SERIALIZABLE
    System.out.println("List of products using serStatement");
    displayProducts(serStatement);

    // delete the new product, change the first product name
    // back to Modern Science, and commit the changes using
    // rcStatement
    rcStatement.executeUpdate(
      "DELETE FROM simple_tbl " +
      "WHERE id = 2"
    );
    rcStatement.executeUpdate(
      "UPDATE simple_tbl " +
      "SET name = 'Modern Science' " +
      "WHERE id = 1"
    );
    rcConnection.commit();

    // close the JDBC objects
    rcStatement.close();
    rcConnection.close();
    serStatement.close();
    serConnection.close();

  } // end of main()


  private static void displayProducts(
    Statement myStatement
  ) throws SQLException {

    ResultSet productResultSet = myStatement.executeQuery(
      "SELECT id, name " +
      "FROM simple_tbl"
    );

    while (productResultSet.next()) {
      System.out.println(
        productResultSet.getInt("id") + "  " + 
        productResultSet.getString("name") + " "
      );
    }

    productResultSet.close();

  } // end of displayProducts()

    
}