Oracle

1. What is high water levelThe high water level is the boundary line in the used and unused space in Oracle, and can also be understood as the dividing line between the data and non-data, but the data file here refers to the data file that stores

Edit the following two files to read as follows:[Email protected] ~]# Cat/etc/oratabHrdb:/opt/u01/app/oracle/product/11.2.0.3/db_1:y--originally N, changed to Y--this path is the installation path for the database[Email protected] ~]#

　　Note: Operations on Oracle should be performed as an administrator as far as possible.　　  　　 to install Oracle, let's be clear: Installing Oracle is divided into installing Oracle services and creating Oracle databases!　　Different computer

[Email protected] ~]# su-oracle[Email protected] ~]$ Sqlplus/as SYSDBASql*plus:release 11.2.0.1.0 Production on Tue Dec 15 09:23:28 2015Copyright (c) 1982, Oracle. All rights reserved.Connected to:Oracle Database 11g Enterprise Edition Release 11.2.0

ProblemThese two days just plsql and Oracle configuration, but in the plsql to insert data, there is a problem, the table in Plsql cannot display Chinese, Chinese cannot save, cannot output, Chinese display question mark in the table,ReasonAfter

Create a table:Cteate table name (column 1 type,column 2 type);view table Structure DESC table nameAdd a field ALTER TABLE name Add (column type);Modify the field type ALTER TABLE name modify (column type);Delete a field ALTER TABLE name drop column

Oracle uses SqlplusInstallation, one-click installation, very simple. The installation process, be sure to remember the passwordTo connect to the local server, you can open cmd directly:Can be directly without landing, if login need to enter the

1: Create UserCreate user username identified by password;Note: The password starts with a letter2: Change Passwordyourself: PasswordOthers: Password username (System administrator can change others)3: Delete UserDrop user username [cascade]DBA

整个系统突然挂掉，su 无法切换用户，修改用户最大进程数后可以登录，重启服务后系统仍不正常，后发现为 plsql 上修改 T_XXX_XXXX 表时有事务未提交，因此排查原因为更改数据没有提交事务，数据库就将表锁住。提交或者回滚事务后系统正常The most likely cause is that the change data does not commit the transaction, and the database locks the table! So when

Sometimes when you need to do a DB efficiency test, you need to simulate a lot of data. You can copy large amounts of data by executing stored procedures based on one raw data:CREATE OR REPLACE PROCEDUREProc_msw_strsql isIINT;BEGINI:=1; whileI100000

Create table spaces and moreSelect Tablespace_name from DBA_TABLESPACES;--DBA permissions user queries the table space in the databaseSELECT * from All_tables where tablespace_name= ' tablespace_name ';--query table space for tables, pay attention

The import and export of Oracle database is an important technical work, not only solves the import and export of the database, but also makes it easier and quicker to obtain the data.Import and export data using imp and expExporting data using

1. Querying the path of Oracle logsSql> Show Parameter Dump_dest name                                  type         VALUE ----------------------------------------------------------------------- ------ background_dump_dest           string      /home/

1) SELECT * from T1 where exists (SELECT * from T2 where t1.a=t2.a);When the T1 data volume is small and the T2 data is very large, the query efficiency of T12) SELECT * from T1 where t1.a in (select t2.a from T2);T1 data volume is very large and T2

--Create a tableCREATE TABLEknet_domain_dns_forwarded (IDVARCHAR2( $BYTE)DEFAULTSys_guid () not NULL, KEYWORDVARCHAR2( theBYTE) not NULL, CNAMEVARCHAR2( +BYTE), URLVARCHAR2( +BYTE) not NULL, Create_date DATEDEFAULTSysdate not NULL, Update_date DATE,

Oracle Database uses sqlplus connection error and direction key garbled solution, oraclesqlplus Connection ErrorAfter the installation, I log on to the enterprise background (http: // ubuntu: 1158/em) and report an error when connecting to oracle

Oracle's rownum principle and usage, and oraclerownum Principle I sorted out and learned some posts from online experts about rownum: References: http://www.cnblogs.com/mabaishui/archive/2009/10/20/1587165.html For the rownum problem in Oracle, many

Explain how to switch between the three modes of Oracle dg and oracledg Oracle dg Switching ==========================================1 maximum performance mode maximum performance ------ default

Simple Oracle REGEXP_INSTR function usage The REGEXP_INSTR function allows you to search for a regular expression pattern string. The function uses the characters defined in the input character set for string calculation. It returns an integer

Oracle DB_LINK, oracledb_link 1. Create a remote database service name first (Note: if the server has both an oracle server and a client, you must configure the service name in tnsnames. ora of the server; otherwise, the following error is reported )