Database Administrator

You may not have used the advantages of these details when optimizing your database. The following are 10 questions about your database performance. Ask yourself.1. assume that your database does not need the ability to store special characters,

I really want to write down my Oracle Installation Process as an accumulation of learning oracle + linux. Environment: VMmachine Version: Linux + oracle, Linux: Red Hat linux release 9 (Shrike), kernel 2.420-8 on an i686 Oracle: 9.2.0.4 1. Install

Create table a (content clob ); Select content from; The displayed content is part of the cotent content and garbled characters. Because a is of the clob type, it cannot be displayed directly from the select result. You need to use the Oracle

A few days ago, the MySQL site held a 12-day Scale-Out activity, listing many successful cases. The figure below each page is very noticeable: Note that HA between the master and slave servers is implemented through DRBD (Distributed Replicated

All these operations are performed in Linux and the root permission is required. Installation start: Shell> groupadd mysql Shell> useradd-g mysql Shell> gunzip | mysql-VERSION.tar.gz | tar-xvf- Shell> cd mysql-VERSION Shell>./configure -- prefix

If you want to import EXCEL or CSV data to MySQL, MySQL's CSV engine is no longer suitable. MySQL CSV engine is provided after 5.0, but does not support WINDOWS. It is only supported by 5.1. The version I tested today is 5.0.45. I. Notes:1. No index.

It is easy to install openser 1.3.1 in Ubuntu Linux, but the configuration is complicated: 1. Connection to the mysql database, instead of using/usr/local/sbin/openser_mysql.sh create (1.2.2) Instead, use/usr/sbin/openserdbctl create, and

The following is in Windows, not in Linux. When querying data using the MySQL command line, screenshots are often used to send posts, such: In this way, the display is not convenient, and the display speed is slow. How to extract data into text:

In some cases, the stored procedure in Oracle becomes invalid. A Red Cross is displayed in the upper left corner of the stored procedure icon in PL/SQL Developer. For example, if the objects referenced in the stored procedure are invalid, dblink may

The role of the control file to the Oralce database is similar to that of the Registry in the Microsoft operating system. The control file is a relatively small binary file that records the structure information of the database. If the Database

I installed Oracle10g on windows2008. After a long time, I found that the normal method would not work. The current situation is that there is no installation package for 10.2.0.3 for vista. This package can be directly installed on windows2008, and

I am familiar with MongoDB because I recently tested MongoDB. MongoDB is still simple, and I have mastered a lot of content in just one week. It is much easier than other databases. I installed: MongoDB version 2.0.8 System: 64-bit Ubuntu

Most of the steps to use hive for data analysis are to use hive to export the statistical results to a local file or other Hive tables, import the local file to mysql or use sqoop to import the Hive table to mysql. Today, my colleague recommended a

Environment: CentOS 6.2 + Oracle 11.2.0.3 Problem description: data cannot be started when oracle is installed or when you configure dataguard, error message ORA-00845: MEMORY_TARGET not supported on this system The main cause of this error is that

This section briefly introduces flashback database, which can be executed in RMAN or SQL * PLUS. Sometimes it is quite practical. Prerequisites: 1: The Archive mode is required. 2: The flash recovery area must be specified. SQL> show parameter

The front-end time is related to a DB project. alanc reports a query. Using indexes is much slower than not using indexes. So I followed up and used explain to look at two different query results. The results of queries without indexes are as

1. Functions of statistical information The CBO-based optimizer in Oracle relies heavily on statistics when generating execution plans. You can understand CBO as a complex mathematical model, statistics are the most important input, and execution

1. Source Code download and preparationPostgreSQL uses the flex and yacc scripts respectively for lexical and Syntax Parsing, that is, the. l and. y files in the source code are generated by them. c and. H files.For more details,

Variable declaration in PL/SQL programmingCreate the first program hello worldbegindbms_output.put_line ('Hello World'); end;/set serveroutput on; (output statement to dos window command) begindbms_output.put_line ('Hello World'); end; /You can see

To access MySQL on CentOS from a Windows client, you need to disable the firewall on CentOS, grant the database user remote access permission, and clear the permission cache. The specific configuration is as follows: [Root @ mysql ~] # Service