[Oracle] oracle 数据库隔离级别学习

//获取连接 省略  
pstat = conn.prepareStatement("select price from books where code='qqq'");  
rs = pstat.executeQuery();  
while(rs.next()){  
  System.out.println("price:"+rs.getDouble(1));  
}  
close();

update books set price=18 where code='qqq';

//获取连接和关闭连接代码 省略  
//不自动提交  
conn.setAutoCommit(false);  
/** 
 * a 查询 
 */  
pstat = conn.prepareStatement("select price from books where code='qqq'");  
rs = pstat.executeQuery();  
while(rs.next()){  
  //输出 price:25.0  
  System.out.println("price:"+rs.getDouble(1));  
}  
close();  
/** 
 * 暂停一会，用pl/sql执行B事务 
 * update books set price=15 where code='qqq'; 
 * commit; 
 */  
Thread.sleep(10000);  
/** 
 * 如果这里再执行a查询的话，和第一次查询结果就不一样，因为中间有B事务的提交更新 
 * 修改，这也是不可重复读 
 */  
//b 更新  
pstat = conn.prepareStatement("update books set price=price+10 where code='qqq'");  
pstat.executeUpdate();  
close();  
//c 查询  
pstat = conn.prepareStatement("select price from books where code='qqq'");  
rs = pstat.executeQuery();  
while(rs.next()){  
  //输出 还是price:25.0 ，因为B事务的干预  
  System.out.println("price:"+rs.getDouble(1));  
}  
close();  
//提交事务  
conn.commit();  
if(conn != null){  
  conn.close();  
}