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对于防火墙来说，很多用户都把他当做一个备用的工具，基本都用杀毒软件了，很少人会想起他，但是防火墙的作用不仅仅在这些地方，还有很多作用是我们没有去了解的，今天就给大家全面介绍下： 方法/步骤 1 引言：　　防火墙技术是建立在现代通信网络技术和信息安全技术基础上的应用性安全技术,越来越多地应用于专用网络与公用网络的互连环境之中,尤以Internet网络为最甚。Internet的迅猛发展,使得防火墙产品在短短的几年内异军突起,很快形成了一个产业:1995年,刚刚面市的防火墙技术产品市场量还

In incomplete recovery, also known as point-in-time recovery, thegoal is to restore the database to its state at some previous target SCN or time.Point-in-time recovery is one possible response to a data loss caused by, for instance, a user error or logical corruption that goes unnoticed for some time.Point-in-time recovery is also your only option if you have to perform a recovery and discover that you are missing an archived log。Your only choice is to recover the database from the point in ti

Automatic Undo Management[@more@]闪回查询（Flashback Query）功能对于误删除或者误更新并且已经commit 了的情况，提供了简便快捷的恢复方法:前提条件数据库必须处于 Automatic Undo Management 状态。SQL> show parameter undo_management最大可以闪回查询的时间段由 UNDO_RETENTION 初始化参数（单位为秒）指定SQL> show parameter undo_retention可以通过 ALTER SYSTEM SET UNDO_RETENTION = <seconds>;来修改参数值使用AS OF 关键字来对表，视图，或者物化视图进行Flashback Query，如果指定了SCN，那么expr 部分必须是

When to Create New Control FilesIt is necessary for you to create new control files in the following situations:All control files for the database have been permanently damaged and you do not have a control file backup.You want to change the database name.For example, you would change a database name if it conflicted with another database name in a distributed environment.[@more@]The CREATE CONTROLFILE StatementYou can create a new control file for a database using the CREATE CONTROLFILE stateme

作者：未知 来源： 转载　[@more@]　1、梨 　　能生津、润燥、清热、化痰。古代医家多用之于食道癌、贲门癌和胃癌。如《滇南本草》云:“治胃中痞块食积。”《本草求原》也曾介绍:“治学业衰少，渐成噎嗝;梨汁同人乳、蔗汁、芦根汁、童便、竹沥服之。”《圣济总录》中还有一便方: “治反胃转食，药物不下; 大雪梨1个，以丁香15粒刺入梨内，湿纸包四五重，煨熟食之。”由于里所含的胡萝卜素、维生素B2、维生素C等都具有一定的防癌抗癌作用，所以梨还适宜鼻咽癌、喉癌、肺癌患者服食。　　食梨小贴士：生梨是人们喜爱的水果，经常食

SELECT SID,SERIAL#,STATUS,SERVER FROM V$SESSION WHERE USERNAME = 'JWARD'; ALTER SYSTEM KILL SESSION 'SID ,SERIAL#';[@more@]

常用电脑的人养眼绝招 [@more@]有一条养眼的做法：把白皑皑的窗口变成淡淡的苹果绿。方法是：桌面-右键-属性-外观-高级-项目-窗口-颜色-其它，色调设为85，饱和度设为90，亮度设为205。然后单击[添加到自定义颜色]-确定...一路确定。 如何调整网页指定的颜色 你要先进行设置，打开浏览器，点击“工具”，点“INTERNET”选项，点右下角的“辅助功能”，然后勾选“不使用网页中指定的颜色”。点确定退出.

SGA ,PROCESS [@more@]SGA:If you decide not to use automatic shared memory management by not setting the SGA_TARGET parameter, you must manually configure each component of the sga.PROCESS :The PROCESSES initialization parameter determines the maximum number of operating system processes that can be connected to Oracle Database concurrently. The value of this parameter must be a minimum of one for each background process plus one for each user process.