Database Administrator

Many of my friends only use Oracle to delete the system. However, in many cases, he may find that the next installation page disappears when the system is re-installed, and he may have to reinstall the system, in fact, this is not the case if your

This article uses four methods to teach you how to use SQL statements to delete duplicate records. Question: How to delete a record with the same field and leave only one record. For example, the table test contains the id and name fields. If there

The lock_sga parameter is not supported on linux. If lock_sga = true is set, a ORA-27126 error is reported at startup.The following is a summary of the steps to use hugetlbfs to simulate lock_sga.1. view the currently used SGASqlplus/as sysdbaSQL *

At the early stage of application system development, due to the relatively small amount of data in the development database, the performance of SQL statement writing is not good for querying SQL statements and writing complex views, however, after

When you submit a query, MySQL will analyze it to see if some optimization can be done to make it faster to process the query. This section describes how the query optimizer works. If you want to know the optimization methods used by MySQL, you can

The interconnection of different database platforms is generally called the heterogeneous service of databases. Currently, all major databases can achieve such Heterogeneous Interconnection, but the specific implementation technologies of different

The default database of Roller is MySQL. In many cases, it is integrated into the existing web system, and the database used in the original web system is not MySQL. Therefore, you have to replace the database when integrating with Roller. Roller's

There are many application projects. At the beginning, MySQL Databases can basically meet various functional requirements. As the number of application users increases and the amount of data increases, MySQL gradually becomes overwhelmed: the

1. For a dual-host system, the code is installed on the local disk, and the database device is mounted on the array.By default, Sybase code is installed under/opt/sybase-12.5　　Under the/opt directory, create the sybase-12.5 directory　　# Mkdir sybase-

(1) back_log:The number of connections that MySQL can have. When the main MySQL thread receives a lot of connection requests in a very short period of time, this works, and then the main thread takes some time (although very short) to check the

1. decompress the Oracle9204 Installation File 1. Oracle 9iR2 (9.2.0.4) (1) simplified process (log on to oracle, release installation files, and use less disk space, faster) When installing LINUX, it is best to divide it into one partition/orasetup.

The solution for all the Administrator passwords in mysql 5.0 is as follows: Use the -- skip_grant_tables option to start the mysql server. At this time, the mysql server does not use the permission table to connect to mysql. Log on directly and

Log on to Linux as an Oracle user Start Oracle: Sqlplus "scott/tiger as sysdba" Startup After entering sqlplus: Take importing and exporting to xzfw as an example. You must have the write permission for/Oracle/oradata/xzfw to perform the

Using shell scripts to monitor and manage Oracle databases will greatly simplify DBA workload, such as common instance monitoring, monitoring, and alarm log monitoring, and database backup, AWR report automatic mail, etc. This section describes how

1. Create an array first Create or replace type t_ret_table is table of varchar2 (20 ); 2. Use a custom function to implement 1. Use the function to return an array.Create or replace function f_split_string (var_str in string, var_split In String)

Q: How can I use Slave to filter delete operations in the MySQL master-Slave replication structure. Problem Analysis: this problem corresponds to the preservation of all records, including the delete records. The granularity of MySQL filter rules

1. SQL and PL/SQL code Terminator SQL code uses ";" to indicate code termination PL/SQL code uses "." To indicate code termination, and uses "/" to indicate code execution. Scott @ ORCL> select * from emp where empno = 7788;   EMPNO ENAME JOB MGR

--- SPFILE is created when you use DBCA to create a database.--- SPFILE must be created on the shared volume or shared raw device--- All instances use the same SPFILE--- If you create a database manually, use PFILE to create a SPFILE.[Oracle @ rac11

1. MySQL-VIP: 192.168.0.50MySQL-master1: 192.168.0.42MySQL-master2: 192.168.0.495. OS Version: CentOS 5.56. MySQL version: 5.5.137. Keepalived version: keepalived-1.2.7.tar.gz  1. MySQL master-master Configuration1. Modify the MySQL configuration

1. Definition Trigger: it is associated with a table or database event. When a trigger event occurs, the trigger defined in the table is triggered and executed. Trigger trigger order 1) execute the BEFORE statement-Level Trigger; 2) for each row