Database Administrator

1. Create an oracle user and dba group; 2. Adjust the system core parameters: #./Idtune SHMMAX 409600000 #./Idtune SEMMNI 15 3. Install the SCO patch file oss459A, Reconnect and restart the core: #/Etc/conf/cf. d/link_unix-y # Init 6　 4. Edit the.

IN Operator SQL statements written IN are easy to write and understand, which is suitable for modern software development.However, SQL statements using IN always have low performance. The following differences exist between SQL statements using IN

1. view all objects currently SQL> select * from tab; 2. Create an empty table with the same structure as Table SQL> create table B as select * from a where 1 = 2; SQL> create table B (b1, b2, b3) as select a1, a2, a3 from a where 1 = 2; 3. Check

1. having clause usage The having clause controls the row groups determined by the group by clause. The having clause conditions allow only constants, clustering functions, or columns in the group by clause. 2. Usage of external join "+" External

A simple Transact-SQL query only includes the select list, FROM clause, and WHERE clause. 1. Simple Query A simple Transact-SQL query only includes the select list, FROM clause, and WHERE clause. They indicate the queried columns, the queried tables

Before introducing the group by and HAVING clauses, we must first talk about a special function in SQL: aggregate function, such as SUM, COUNT, MAX, and AVG. The fundamental difference between these functions and other functions is that they

With the release of Oracle8i, Oracle supports two major programming languages, PL/SQL and Java. Today, many Oracle customers use both PL/SQL to create database applications and Java to create database applications. Since there are two database

This White Paper also provides a Configuration Wizard for the database engine. NET Framework programming API. It also provides recommendations for the encoding, change, and release management process, and these recommendations should be appropriate

Oracle claims that the installation of the Oracle9i database in Linux requires at least MB of memory and at least 1 GB or two times of memory swap space. For servers with a system memory larger than 2 GB, the swap space can be between 2 gb-4gb. If

Attracting customersBlog of Oracle: instances and databases Instances are composed of the following: SGA, Sharedpool, Databasebuffercache, and Redologbuffercache. A database consists of physical files. The required files include data files, control

I. Historical Background The full-Text retrieval technology of Oracle databases is already perfect. Oracle Text enables Oracle9i to have powerful Text retrieval capabilities and Intelligent Text management capabilities. Oracle Text is the new name

I wrote an article about AIX tuning a few years ago, and now AIX 7 has appeared, so it is necessary to review the basic tuning measures that need to be performed on the AIX system. Many of the released technical levels (TL) and some suggestions may

As we all know, Microsoft Excel can input, collect statistics, and generate charts intuitively and conveniently. However, it has limited data management capabilities and lacks the ability to query a large amount of data, if you use its advantages in

We often hope to unify data stored in different regions for application. Now we can use the replication technology to solve this problem. However, Database Replication also requires some conditions.First, the database must have the Advanced

When talking about databases, you cannot talk about database storage, and you cannot talk about database space management. Here we mainly talk about the space management issues of IDS. Physically, IDS manages pages and chunks. Logically, IDS manage

The following parameters in onconfig in the Online configuration file have a significant impact on CPU utilization. • NUMCPUVPS• SINGLE_CPU_VP• MULTIPROCESSOR• AFF_NPROCS• AFF_SPROC• NUMAIOVPS• OPTCOMPAND• NETTYPENUMCPUVPS, MULTIPROCESSOR, and SINGL_

I. Prerequisites for restoration When ontape backup is used to recover data to another server, the environment is as follows: 1. The two server models are the same as those of the e-hpc series)2. Same Operating System (HP-UXB.11.00), database

Informix-Online databases are widely used for their high performance, high reliability, and support for data integrity definition/check. For databases in use, the security and reliability of data backup has become the focus of attention. Based on

IntroductionBoth DBAs and developers like indexing. They can accelerate query and search, especially in a data warehouse environment, because the database will receive many ad-hoc requests. To avoid full table search, we usually create an index in

Only with a clear understanding of these issues can we select a suitable connection method for specific query needs and develop robust database applications. Selecting an appropriate table connection method has a crucial impact on the performance of