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index unique scanindex range scanindex full scanindex fast full scanindex skip scanIndex unique scan~~~~~~~~~~~~~~~~~Method for looking up a single key value via a unique index.always returns a single valueYou must supply AT LEAST the leading column of the index to access data viathe index, However this may return > 1 row as the uniqueness will not beguaranteed.[@more@]example explain plan:SQL> explain plan forselect empno,ename from emp where empno=10;Query Plan---------------------------

最近一OLTP生产数据库采用物化视图后性能明显提升，越来越发觉物化视图是把利器了。今天继续尝试物化视图中的一些奇妙的地方。如下是案例的整个过程，供大家学习和引用！[@more@]1、先创建两张表test_1和test_2：SQL> conn shiyihai/shiyihai@db80Connected to Oracle9i Enterprise Edition Release 9.2.0.6.0 Connected as shiyihaiSQL> SQL> drop table test_1;Table droppedSQL> create table test_12 (3 test_date date,4 id number(8),5 address varchar2(24)6 );Table createdSQL> drop table test_2;Table droppedS

Server Configuration [ ] Create the database [ ] Determine and set sizing parameters for database structures [ ] Create and manage temporary, permanent, and undo tablespaces [ ] Stripe data files across multiple physical devices and locations [ ] Configure the database environment to support optimal data access performance [ ] Create and manage database configuration files [ ] Create and manage bigfile tablespaces [ ] Create and manage multiple network configuration files [ ] Create and configur

All the files needed to recover a database from a media failure or a logical error are contained in the flash recovery area. The files that can reside in the flash recovery area are as follows:Control filesA copy of the control file is created in the flash recovery area when the database is created. This copy of the control file can be used as one of the mirrored copies of the control file to ensure that at least one copy of the control file is available after a media failure.[@more@]Archived lo

There are several new other background processes in 10g/11g,as following：MMON performs various manageability-related background tasks, for example:*Issuing alerts whenever a given metrics violates its threshold value*Taking snapshots by spawning additional process (MMON slaves)*Capturing statistics value for SQL objects which have been recently modifiedMMNL stands for manageability monitor light which is responsible to flush the information to the repository and performs frequent and light-weig

今天一部门开发人员通过公司BQQ问我是否可以在脚本中获取到update语句执行后的更新行数，并想知道返回值。我做了一个小试验，如下的内容很适合他借以利用。这个案例的关键字有sql%notfound、sql%rowcount和return，适合在脚本或应用中加以使用。[@more@]SQL> create table test_return 2 ( 3 name varchar2(24) 4 );Table createdSQL> insert into test_return values('111');1 row insertedSQL> insert into test_return values('222');1 row insertedSQL> commit;Commit completeSQL> SQL> set serveroutput o

The ORACLE_DATAPUMP access driver unloads data from an Oracle database to a flat file (DPAPI format) using the external table method. The external table must be created using the CREATE TABLE ... AS SELECT ... (CTAS) method. You can specify the PARALLEL clause when creatingthe table; ORACLE_DATAPUMP access driver unloads data into multiple flat files at the same time. One parallel execution server will write to only one file at a time. Unloading data in the context of external table means creati

1、Client-Side Query CacheThis feature enables caching of query result sets in client memory. The cached result set data is transparently kept consistent with any changes done on the server side.Applications leveraging this feature see improved performance for queries which have a cache hit. Additionally, a query serviced by the cache avoids round trips to the server for sending the query and fetching the results. It also reduces the server CPU that would have been consumed for processing the qu

Oracle Database Standard Edition One Oracle Database Standard Edition One delivers unprecedented ease of use, power, and performance for workgroup,department-level, and Web applications. From single-server environments for small business to highly distributed branch environments, Oracle Database Standard EditionOne includes all the facilities necessary to build business-critical applications.[@more@]Oracle Database Standard Edition Oracle Database Standard Edition delivers the unprecedented ease

北京2008年奥运会赞助企业如下： [@more@]奥林匹克全球合作伙伴北京2008合作伙伴 赞助商独家供应商 供应商　　英孚教育水晶石数字科技元培翻译德尔地板奥康立白普华永道盟多

谁有《美国口语大观》的mp3听力资料？能否分享给我，非常感谢！[@more@]

新登陆的客户端无法登陆上数据库，抛了一堆堆栈和memory的异常。赶紧上os主机上，看看是否有告警信息。查了一下告警日志很正常，没有特别的异样信息出现。查询后台进程信息，如下：[oracle@linux3200 log]$ ps -ef |grep ora_[@more@]oracle 7704 1 0 Nov07 ? 00:00:44 ora_pmon_db3200oracle 7706 1 0 Nov07 ? 00:00:06 ora_psp0_db3200oracle 7708 1 0 Nov07 ? 00:00:04 ora_mman_db3200oracle 7710 1 0 Nov07 ? 00:00:19 ora_dbw0_db3200oracle 7712 1 0 Nov07 ? 00:03:44 ora_lgwr_db3200oracle 7714 1 0 Nov07 ? 00:00:32 ora_ckpt_d

DBNEWID is a database utility that can change the internal, unique database identifier (DBID) and the database name (DBNAME) for an operational database. The DBNEWID utility lets you change any of the following:[@more@]Only the DBID of a databaseOnly the DBNAME of a databaseBoth the DBNAME and DBID of a databaseTherefore, you can manually create a copy of a database and give it a new DBNAME and DBID by re-creating the control file, and you can register a seed database and a manually copied datab

If it was going to easy, it never would have started with something called labor!Shouting to make your children obey is like using the horn to steer your car, and you get about the same results.To be in your children’s memories tomorrow, you have to be in their lives today.[@more@]The smartest advice on raising children is to enjoy them while they are still on your side.The best way to keep kids at home is to give it a loving atmosphere and hide the keys to the car.The right temperature in a ho

This document assumes that you are doing the Backup and Recovery basics- Running in Archivelog mode- multiplexing the controlfile- Taking regular backups- Periodically doing a complete restore to test your procedures. [@more@]Questions and Answers1. Turn on block checking.REASON: The aim is to detect, very early the presence of corrupt blocks in the database.This has a slight performance overhead, but Checksums allow Oracle to detect earlycorruption caused by underlying disk, storage system, or

This short article describes several features of Oracle which may be used on new databases to help detect problems as close to when they occur as possible. Some of these features are publicly documented and some are not. All should be used with extreme care.[@more@]DBVERIFY~~~~~~~~ DBVERIFY (also known as DBV) performs similar checks to the block checking described above but it is a stand alone tool which can be run against an Oracle datafile. Most Unix platform

In Oracle databases, corruption in its broadest sense is incorrect information - information that Oracle did not expect to find. This condition can exist in memory, in data blocks, or in the data dictionary, giving rise to the five forms of corruption:Memory (HEAP) corruptionBlock corruptionDictionary corruptionUndo corruptionRedo corruption[@more@]HEAP corruption occurs when a piece of memory is overwritten and this can be caused by an Oracle Bug, an O/S overwrite, or by an application. The cod

上个礼拜在帮忙一同事解决expdp时碰到三个异常错误，今天总结如下：首先遇到的异常如下：[oracle@linux3200 oracle]$ expdp system/wicp_annie@db3200 directory=dir_expdp dumpfile='wicp_all_071026.dmp';[@more@]Export: Release 10.2.0.1.0 - Production on Thursday, 25 October, 2007 20:56:51Copyright (c) 2003, 2005, Oracle. All rights reserved.Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - ProductionWith the Partitioning, OLAP and Data Mining optionsORA-31626: job does not existORA-

最近在将一heap日志表调整为partition的日志表时，发现一个问题，那就是查询分区数据时无法直接按变量来进行查询。过程如下：insert into t_actionlog_backupselect * from t_actionlog partition(v_partition_name)[@more@]其中v_partition_name是我程序中传入的分区名称变量，结果无论我怎么调试都抛异常“ORA-02149: 指定的分区不存在”。我直接在sql提示符下执行都是没问题的。见如下的过程：declarev_partition_name varchar2(20);beginv_partition_name :='p_20071016';insert into t_actionlog_backupselect * from t_actionlog pa

下面是一个linux下磁盘分区的案例，这里只贴出来其中的操作过程，供大家学习！[root@portal3115 ~]# fdisk -lbash: fdisk: command not found[root@portal3115 ~]# /sbin/fdisk -l[@more@]Disk /dev/cciss/c0d0: 291.3 GB, 291331192320 bytes255 heads, 63 sectors/track, 35419 cylindersUnits = cylinders of 16065 * 512 = 8225280 bytesDevice Boot Start End Blocks Id System/dev/cciss/c0d0p1 * 1 13 104391 83 Linux/dev/cciss/c0d0p2 14 267 2040255 82 Linux swap/dev/cciss/c0d0p3 268 5379 41062140 83 Linux/dev/cciss/c0d0