Database Administrator

I. Oracle 9i has two undo management methods:AUM Automatic Undo ManagementMUN Manual Undo ManagementWe recommend that you use AUM.Undo segment is also called rollback segment. Ii. Three major functions of undo:1. provide Consistent Read2. roll back

The auto-increment column here mainly refers to the auto-increment of the primary key id in a table. Unlike Mysql, Oracle cannot set the auto-increment column feature when creating a table in CREATE. Oracle must automatically add columns by creating

Oracle provides three technologies for SYSDBA Auditing: 1. Database Audit user privileges, commands executed and tables accessed, and logon status 2. Use a database trigger to initiate a value-based audit; 3. fine-grained auditing can track which

WHEN handling exceptions, pay special attention to the use of when others then, because when others then will eat all the exceptions. If no information is thrown after when others then, that is, when others then null, this may greatly increase the

I always wanted to deploy phppgamdin, But I encountered different problems when installing phppgamdin in RedHat and Windows. Because I am not familiar with the web stuff, I finally ended up failing. For details, see: On the weekend, I was suddenly

1. Start the database server (posgres user ): [S @ localhost bin] $ postgres-D/opt/postgresql/data/>/opt/postgresql/log/pg_server.log 2> & 1 & [1] 4508 Of course, if environment variables are set PGDATA=/Opt/postgresql/data Export PGDATA You

In fact, MapReduce in MongoDB is more similar to GroupBy in relational databases. Just after doing this experiment, the GroupBy (MapReduce) for large data volumes is still ideal, generating million 3-bit random strings For(VarI = 0; I {  VarX ="

After installing MySQL 5.6 with rpm on RedHat5.5, see The following message is displayed when you use mysqladmin to change the password (mysqladmin-u root password "mysql "). Mysqladmin: Can't turn off logging; error: 'Access denied; you need the

This error may occur when you use RMAN to restore SPFILE from AUTOBACKUP. Here is a brief summary. When RMAN recovers SPFILE, the following error may occur: RMAN> restore spfile from autobackup; Start the restore on March 10-11Use channel ORA_DISK_1

The remote database user test has a t table. SQL> showUser USERIs"TEST" SQL>Select*FromTab; TNAME TABTYPE CLUSTERID ----------------------------------------------- TTABLE SQL>! Cat/etc/hosts # DoNotRemove the following line,OrVarious

There is a need for a job to record all its value-added service operation information It is impossible to delete the original data when recording, so I thought, is there a syntax for MYSQL, instead of selecting the original data and then updating,

1. Patch preparation There are four main points:1) use Telnet to log on to the application server and check the Unix server type. Currently, there are three types of server (ibm aix, SUN Solaris, and hp ux.2) view the version number of the program

Create table test1 (id number, name varchar2 (20 ));Create table test2 (id number, name varchar2 (20 ));Create table test3 (id number, name varchar2 (20 )); 1. No commit is displayed in t1; Create or replace procedure t1AsBeginFor I in 1 .. 10000

D: \ test. SQL script: Select& 1From& 2; Exit; Run the following command to pass the parameter: sqlplus "scott/tiger @ test" @ d: \ test. SQL sysdate dual Note: The parameter must be represented by & [1-9]. Otherwise, you will be prompted to

Dynamic SQL loop traversal using Oracle dynamic cursors Create Or Replace ProcedureP_TEST_ SQLIs TYPE ref_cursor_typeISREFCURSOR;-- Define a Dynamic Cursor Tablename varchar2 (200)Default 'Ess _ client'; V_ SQL varchar2 (1000 ); Mobile varchar2

Dbms_mview.refresh ('table name', 'F') -- fast refresh, that is, incremental refreshDbms_mview.refresh ('table name', 'C') -- completely refreshWe often use materialized views to synchronize or migrate data. In the refreshing process of dbms_mview,

Note: System Version ------ MacOS X 10.6.8 Mysql version ---- the latest official website version 5.5.19 1. Download the installation file from the MysqL website. Download the installation file from the Mysql official website, download entry:

1. Environment DescriptionMysql manager node: 192.168.0.1MysqlServer node: 192.168.0.100Mysql node: 192.168.0.160Mysql node: 192.168.0.161Note: At least four servers are required for the mysql cluster. We recommend that you add five more MySQL

Configure parameters according to the manual... [Oracle @ www.bkjia.com ~] $/Mnt/runInstaller-record-destinationFile/tmp/install_database.rspStarting Oracle Universal Installer... Checking installer requirements... Checking operating system version:

Background Statistical queries are time-consuming queries. The usage scenario is that QPS is not large. Each Query Needs to access a large amount of data and process a large amount of data for a long time (usually more than seconds ). Analysis A