Database Administrator

There is a stored procedure, which already has four dblinks, but due to business needs, a few more needs to be added. When it is added to the fifth, the system suddenly throws an error: ora-02020 too relational database links in use. Consulting

1. Try not to use like '%' 2. For like '%' (not starting with %), Oracle can apply the index on colunm 3. For like '%... '(Not ending with %), you can change it to like' % 'in the form of reverse + function index' Create a test table and Index. Note

-- Oracle method 1SELECT * FROM(Select a. *, rownum rn from (SELECT * FROM ss_custinfo)Where rownum )Where rn> = 21; -- Oracle method 2SELECT * FROM(Select ss. *, rownum rn from ss_custinfo ss)WHERE rn = 21;  -- Oracle method 3SELECT *

An interesting question about Oracle databases: COSCO created an oracle instance zycw before the disk array was added, and a new instance zync was created after the disk array was added. In order to save system resources, we plan to enable only the

The Oracle database update was used a few days ago, but there were a lot of problems with this simple problem. Therefore, we will search online materials and summarize them here for temporary use. The SQL statements listed below are based on the

SGA is the memory area used to store database information, which is shared by database processes. It contains data and control information of the Oracle server. It is allocated in the actual memory of the computer where the Oracle server resides. If

When I was working on a project today, a problem occurred while inserting data into the table. The database reported a violation of the unique constraint and the solution was simple: The project uses the Oracle database. In the early stage, I

Article 1: First, you must have a table! Create table example ( ID Number (4) not null primary key, Name varchar (25 ), Phone varchar (10 ), Address varchar (50) );   Then, you need a custom sequence Create sequence emp_sequence Increment by 1 --

Operating System: RHEL 1, 5.4 Download MySQL 5.1.54: Wget http://mysql.ntu.edu.tw/Downloads/MySQL-5.1/mysql-5.1.54.tar.gz-c Download SphinxSE 1.10-beta: Wget http://sphinxsearch.com/downloads/sphinx-1.10-beta.tar.gz-c Detailed operation steps: Cd

MySQL uses the memory pool structure. It is quite simple to understand this structure, but it is hard to understand the allocation process in my_alloc.c./*Data structures for mysys/my_alloc.c (root memory allocator)*/# Ifndef _ my_alloc_h# Define _

In the following code, some struct types are unclear, such as THD, st_vio, and pollfd. However, we can see that MySQL uses the Select model to receive client connections. It is also found on the internet that unix_sock refers to the communication

The parameter file of Oracle RAC is different from the parameter file of a single instance. Therefore, when modifying the parameter file, pay attention to it. First, set the archive path: SQL> alter system set log_archive_dest =

The shared pool is mainly composed of data_dictionary that saves the data dictionary and the library cache that saves the SQL and PL/SQL code and execution plan. It also includes several other buffers for different system features and technologies,

SQL * PLUS allows you to create a login. SQL file. This script is executed every time SQL * PLUS is started. In addition, you can create an SQLPATH environment variable. In this way, no matter which directory the login. SQL script is located, SQL *

1. The steps for compiling an Oracle stored procedure are as follows: Create or replace procedure P_AUTO_CREATE_PARTITION (Result Out int, LogErrDesc Out varchar2 ) Is Type TypeTable is table of varchar2 (20 ); CreatePartitionErr exception;

In the morning, the Provincial Social Security Project Team responded that the database had a system-type SQL statement, which occupied a lot of resources and seriously affected the database performance. The specific SQL statement is: Select count (

The security management mechanism of Oracle10g listeners and oracle9i have been greatly changed. The Listener security mechanism uses the Password and Local OS Authentication methods. When Local OS Authentication is used, even if a listener password

Write a test program when using C in Linux to operate MySQL database IntMain (Void) { MYSQL m_mysql; Mysql_init (& m_mysql ); Const CharPLocalhost [] ="Localhost"; Const CharPUser [] ="Root"; Const CharPPass [] ="123456";

 1. Related Concepts The concept of Rowid: rowid is a pseudo column. Since it is a pseudo column, this column is not user-defined, but added by the system itself. Each table has a pseudo rowid column, but the table does not physically store the

After Oracle is installed, the installation is successful, but errors occur when dbca and netca are running.[Oracle @ db1 ~] $ Netca Oracle Net Services Configuration:## An unexpected error has been detected by HotSpot Virtual Machine:## SIGSEGV