Database Administrator

1. query the list of log files used:Select * from v $ log; 2. query the log files of the Group in use:Select * from v $ logfile; 3. Force log switching:Alter system switch logfile; 4. query historical logs:Select * from v $ log_history; 5. Log

Snap is used to extract one or more tables from a database to the local database. The operations are as follows: -- Glossary: Source-database to be synchronized -- Purpose -- database to be synchronized /* 1. Create a dblink :*/ -- 1. Create dblink

1. select an appropriate Oracle optimizer There are three optimizer types in Oracle: A. RULE (based on Rules) B. COST (COST-based) C. CHOOSE (optional) Set the default optimizer. You can declare the OPTIMIZER_MODE parameter in the init. ora file,

After mysql is compiled and installed in the Linux source code, the installation path is modified. However, an error is reported after the environment variable is set, as follows: [Root@www.bkjia.com var] # mysqld_safe -- user = mysql & [1]

I.Preparations1.Valid backupBe rightOracle softwareAnd physical backup of the database.2.Check for invalid objects.3.EnsureSYSTEMFree Space in50 MAbove.4. SHARED_POOL_SIZEAndJAVA_POOL_SIZEAt least150 Mb.5.Shut down the databaseOracleProcess.6.Backup

By default, MySQL only allows local access. If you want other machines to remotely access this Mysql database, you need to set something. Next we will step by step: 1. Configuration File Modification1. # sudo vim/etc/mysql/my. conf Find

Several important MySQL DirectoriesDatabase directory/var/lib/mysql/ Configuration File/usr/share/mysql (mysql. server command and configuration file) Related commands/usr/bin (mysqladmin mysqldump and other commands) Start script/etc/rc. d/init. d/(

Library cache is a part of the Shared pool, which is almost the most complex part of the Oracle memory structure. It mainly stores information about shared curosr (SQL) and PLSQL objects (functions, procedure, trigger, and the table, index, view,

I. B-Tree indexes 1. Principles for selecting index fields: The most frequently used field in the where clause Join fields in a join statement Select highly selective fields (if a few fields have the same value and there are many unique values,

Summary: In data migrate, the constraints on some tables are always bothering us, making migratet difficult. How can we use the attributes of constraints to solve these problems? This article describes in detail the four attributes of constraints:

Oracle 11g R2 explicitly states that export and import are no longer supportedReason for elimination: Import and Export speed is slowAlternative: Data Pump, speed increased by 5 times, but cannot be remotely imported or exported, only on the

QL> set line 130 SQL> select name, created, log_mode, open_mode from v $ database;   Name created LOG_MODE OPEN_MODE ---------------------------------------------------------------------------------------------- MDSP 30-OCT-10 ARCHIVELOG READ WRITE  

This chapter describes how to handle the "handling material handling tickets" error?Main signs:1. If this option is selected, pressing "process" does not work.2. You cannot view "View/update allocation (U)"3. "Source sub-stock" is empty.For example:

ORA-01502: index 'xxx. xxxx' or partition of such index is in unusable state. Solution: Log On With DBA and run the following script. -- Log On with the DBA permission and execute -- Fix all indexes in the UNUSABLE status and rebuild them.

SELECT * FROM TableLIMIT[Offset,]Rows|Rows OFFSET offset The LIMIT clause can be used to force the SELECT statement to return the specified number of records. LIMIT accepts one or two numeric parameters. The parameter must be an integer constant. If

What is a table?? Table: tableLogically, each table contains rows and columns in the database. The table can be 0 rows, but at least one table must support index query. Physically, each table is saved on a disk by one or more files. Each table is

Install the first Binary source code ready, you can download from the image Sohu: http://mirrors.sohu.com/ My website is mysql-5.5.15-linux2.6-i686.tar.gz,Linux version 2.6.18-164. el5 In actual work, the configurations of virtual machines may be

In Oracle, we all know that the two single quotes are character-type, But how should we write single quotes in a script. Of course, you can use '''' (four single quotes) to assemble a single quotation mark. In plsql, how do you update text

Check memory and swap partition size# Grep MemTotal/proc/meminfo# Grep SwapTotal/proc/meminfo Check disk space size# Df-h Check the libaio package. CentOS 4.8 is not installed by default.Note: The error "ORA-12547: TNS: lost contact" is reported

Opening the cmd command line is definitely not a mysql command line. The first time I was wrong in this place, I was depressed for a long time. Command for backing up MySQL database Mysqldump-hhostname-uusername-ppassword databasename> backupfile.