Database Administrator

1. flashback database1. Applicable scenarios:1) delete users by mistake2) truncate table3) Multi-table data chaos2. Database flashback Conditions1) configure the database to archive2) configure the flash recovery area (FRA: flash recovery area)SQL>

Oracle has two permissions: System privileges: operations performed by the user may affect the data dictionary; Object privileges: operations performed by users may affect data;   System Privilege: There are more than 200 system permissions. Common

Back up archived logs -- View the archive logs generated by the first archive location in the past day. dest_id indicates the location where archive logs are stored, corresponding to 1 ~ in v $ archive_dest ~ The value of the destination field of 10.

1. Export Export with PLSQL Export table structure: Tools --> Export User Objects (Export User object) --> select the table to be exported (including Sequence and so on) -->. SQL file, all exported are SQL files Export table data: Tools -->

How to sort fields in Oracle in the form of Chinese characters and numbers: For example: Order ByNLSSORT (field name,'Nls _ SORT = SCHINESE_PINYIN_M'), To_number (translate (field name,'123'| Field name,'123'))  NLSSORT () function: If the

InnoDB in mysql 5.5 serves as the default database storage engine, and after the mysql-5.1 upgrades mysql to the mysql-5.5, the following programs need to recompile and install the upgrade:PHP 5.3.6Cacti spinePureftp InstallWget http://dev.mysql.com/

Oracle PL/SQL Nested Table Test Code: Connected to Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 ConnectedAsXxpo SQL> CREATE OR REPLACE TYPE color_tab_t AS TABLE OF VARCHAR2 (30 ); 2/ Type created SQL> SQL> CREATE TABLE

, A, B, and C collections are correlated. The number is the value of document. For more information about DBref, see this article. Create A collection first. > Var a = {value:"1"} > Var B = {value:"2"} > Var c = {value:"9"} > Var d = {value:"10

Currently, most websites using MySQL use Memcache as the key-value cache at the same time. Although such an architecture is extremely popular and there are many successful cases, it relies too much on Memcache to virtually make Memcache the root

There is a MySQL database with more than 1.1 billion records because of its working relationship. I thought that the query performance of the MyISAM engine would exceed InnoDB. I tried it these two days, but because the data volume is too large, the

Running Environment CentOS 5.6 Hadoop hive Sqoop is a tool developed by clouder for hadoop technology support to import and export data between relational databases, hdfs, and hive. Read more: Sqoop configuration and installation 1. Install sqoop

Creating and Deleting Users is a common operation in Oracle user management, but it implies the knowledge of the system and object permissions of the Oracle database system. Understanding the Authorized operations and principles of Oracle users can

Sequence usage in Oracle: Create table test(Pid integer primary key,Name varchar (20));Select * from test;Insert into test values (1, 'jack ');Create sequence test_seq; -- create a sequenceSelect test_seq.nextval from dual; -- add one after each use

The materialized view stores the View query results to a real table based on the query definition. When you query data in the materialized view, Oracle does not search for a specific base table, this will greatly improve the efficiency. First, let's

1. Go to the official website of Apple to download and support your system JAVA. You need to install the Lion system separately. Snow Leopard comes with JAVA and only needs to update the new version. The address is this

In the Patchset of Oracle 10g version, only one file Disk1. the size of the Patchset in Oracle 11.2.0.2 and 11.2.0.3 is greatly increased. The Patchset of 11.2.0.2 and 11.2.0.3 is 5 GB. These 5 GB files are composed of seven files. It is a

Automatic Storage Management Background (ASMB) process: the ASMB process runs in the database instance that uses ASM. It is responsible for communicating with the management and storage ASM instance, providing updated statistics to the ASM instance,

1. Log On As root and enter the command sudo gedit/etc/mysql/my. cnf on the terminal in the open file.Find the [client] and add it belowDefault-character-set = utf8Find [mysqld_safe] and add it belowDefault-character-set = utf8Find [mysqld] and add

For more information about Oracle execution plans, see Oracle Explain Plan. 1. view the SID of the current sessionSYS @ anqing1 (rac1)> select userenv ('sid ') from dual;USERENV ('sid ')--------------137SYS @ anqing1 (rac1)> select sid from v $

Use ctrl + c to exit the current status output mode. Run the following command: expdp userid/password attach = job_name to connect to the currently running import/export task. You can use job_name to specify the task name. 1. add_file = test _ % U.