Database Administrator

It has been a month since Oracle was installed on Linux. after hitting the wall several times, I finally successfully installed Oracle11g and Oracle10g. There is no time to write step by step. For those steps, see the ORACLE Installation Guide.

1. Replace DISTINCT with EXISTS to eliminate sort operation 2. If you filter data in group by, specifying conditions in the WHERE clause has better performance than HAVING clause. Because data has been filtered out before the GROUP, fewer rows are

What is the file structure of the MySQL database? For the Database Command created in this way: Create database mysqldb The default database storage location contains a folder named mysqldb. To operate the database, you must stop the database

Recently, I encountered a server that used Oracle databases. After learning Oracle + for advice, I finally got all the user passwords on the website background management interface. I found it too troublesome to operate Oracle, in order to avoid

Ubuntu Navicat for MySQL installation: 1. Navicat for MySQL official download 2. decompress the tar file after the download.Tar-zxvf navicat8_mysql_en.tar.gz 3. decompress the package and run it in the decompressed directory. ./Start_navicat

Use dbv and rman blockrecover to repair bad Oracle Database blocks. (1) alert. log reports the following error during rman backup: Fri Jul 2 12:41:36 2010 Hex dump of (file 12, block 2718618) in trace

1.download and install mysql-5.5.30.tar.gzand cmake.2.8.11.2.tar.gz (1) install cmake first (after mysql5.5 is compiled through cmake) [Root @ rhel5 local] # tar-zxv-f cmake-2.8.11.2.tar.gz[Root @ rhel5 local] # cd cmake-2.8.11.2[Root @ rhel5 cmake-2

I. orion Overview1. DescriptionOrion is a tool provided by Oracle to test io performance. It can be used to simulate Oracle Database IO, or to simulate the Strip function of ASM. 2. Advantages and Disadvantages of orion2.1 AdvantagesNo need to run

Take PostgreSQL 9.2 official document as an example: Create table weather (City varchar (80 ),Temp_lo int, -- low temperatureTemp_hi int, -- high temperaturePrcp real, -- precipitationDate); Insert into weather VALUES('San Francisco ', 46, 50, 0.25,

The default installation path of the mysql database is/var/lib/mysql. However, in practice, we often need to customize the installation path, such as/data/mysql, or/opt/mysql is usually a separate disk or partition, which is conducive to performance

Because of the sudden power failure in the office, the database was not restarted after the server was restarted, so I found that all the databases were not set to automatically restart after the boot, in order to prevent the server from restarting

1. first, I will use the decimal type for high-precision items, such as money, and will not consider float and double, because they are prone to errors. numeric and decimal are synonymous, and numeric will automatically convert to decimal. DECIMAL

I. SCN description I have also compiled several Oracle SCN articles as follows: An in-depth study on the relationship between the time modification problem and SCN of the Oracle DB Server System Description of Oracle Blockscn/commit scn/cleanout scn

Environment: you can download the CentOS 5.9 Enterprise Edition official websiteVirtual Machine virtualBoxOracle 11g R2 posts:Http://www.oracle.com/technetwork/database/enterprise-edition/downloads/112010-linx8664soft-100572.html1. Briefly describe

There are two main causes:1. There is a large volume of transactions that allow Oracle Undo to automatically expand, resulting in excessive disk space occupation;2. There are large transactions that have not been contracted or are not committed by

Complete MySQL installation and master-slave dual-machine configuration Example HOST: 192.168.0.1 example slave: 192.168.0.2 ################### Complete mysql installation ################## # Groupadd mysqlUseradd-g

Environment:Database Version: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0VBOX Virtual MachineHost Name, database instance, database name, and IP address planning:Source Host IP Address: 192.168.1.213 HOSTNAME: bys001.oel.comTarget Host

Required dependent LibrariesConfig: IniFilesMIME: LiteDBD: mysqlDBISys: SyslogWe recommend that you use CPAN for installation. First, obtain the global read lock, write the data in the cache to the disk, then execute the LVM snapshot, and finally

If you delete a non-existing TABLE in Oracle, such as "drop table notExistTable", the following message is displayed: ORA-00942: Table or view does not exist, If you run this statement using a program, an exception is reported. You need to delete

1 problem: As mentioned above, a materialized view for timed refresh is created in my project. This materialized view is based on the query of a table with two remote machines connected to the left. For the previous article "materialized views of