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oracle flashback
flashback database要求数据库必须处于归档模式1) how to check if flashback function and log mode is open select dbid, name, log_mode,flashback_on from v$database; --FLASHBACK_ON为NO,则表示闪回特性尚未启用 (Ano原创 2012-08-01 22:22:09 · 271 阅读 · 0 评论 -
oracle isolation level
隔离级别(isolation level) l 隔离级别定义了事务与事务之间的隔离程度。l 隔离级别与并发性是互为矛盾的:隔离程度越高,数据库的并发性越差;隔离程度越低,数据库的并发性越好。l ANSI/ISO SQL92标准定义了一些数据库操作的隔离级别:l 未提交读(read uncommitted)l转载 2012-07-22 23:26:40 · 1518 阅读 · 0 评论 -
oracle 初学者常见问题
1. Oracle安装完成后的初始口令? internal/oracle sys/change_on_install system/manager scott/tiger sysman/oem_temp2. ORACLE9IAS WEB CACHE的初始默认用户和密码? administrator/administrator3. oracl转载 2012-07-24 06:42:19 · 2484 阅读 · 0 评论 -
oracle flashback query
在Oracle 10g中,Flash back家族分为以下成员:Flashback DatabaseFlashback DropFlashback TableFlashback Query(分Flashback Query,Flashback Version Query,Flashback Transaction Query)下面介绍一下Flashback Query转载 2012-07-24 23:05:18 · 444 阅读 · 0 评论 -
redo vs undo
redo--> undo-->datafileinsert一条记录时, 表跟undo的信息都会放进 redo 中, 在commit 或之前, redo 的信息会放进硬盘上. 故障时, redo 便可恢复那些已经commit 了的数据.redo->每次操作都先记录到redo日志中,当出现实例故障(像断电),导致数据未能更新到数据文件,则数据库重启时须redo,重新把数据更新到数据文件转载 2012-07-25 15:39:52 · 349 阅读 · 0 评论 -
oracle instead of trigger
A view presents the output of a query as a table. If you want to change a view as you would change a table, you must create INSTEAD OFtriggers. Instead of changing the view, they change the underlyi转载 2012-07-26 22:24:41 · 568 阅读 · 0 评论 -
truncate drop delete difference
DELETEThe DELETE command is used to remove rows from a table. A WHERE clause can be used to only remove some rows. If no WHERE condition is specified, all rows will be removed. After performin转载 2012-07-28 16:58:48 · 355 阅读 · 0 评论 -
Io 异常: The Network Adapter could not establish the connection
Check the host addresslistener 与tns不匹配 tnsping ora9iAttempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.123)(PORT = 1521))) (CONNECATA = (SERVER = DE转载 2012-09-23 22:22:03 · 356 阅读 · 0 评论 -
oracle RAC setup
1. 安装操作系统,准备软件2.hosts文件,检查所需软件包3.配置系统内核参数hangcheck-timer4.设置shell5.系统安全设置6.创建oracle用户和组7.设置oracle用户环境变量8.配置节点间信任9.配置共享存储10.创建和配置raw设备11.安装oracle clusterware12.安装oracle数据库13.配置O转载 2012-12-01 22:16:40 · 337 阅读 · 0 评论