Database Administrator

I. Traversal Each node in the index tree is a page. The index tree has three types of nodes: root node, intermediate node, and leaf node. (1) like an intermediate node, the root node only contains the entry value and entry pointer of the next node.

A few days ago I wrote something btree (http://thuhak.blog.51cto.com/2891595/1261783), continue this idea today, continue to write B + tree. In addition, B + tree is my goal. I have a better understanding of the basic principles of file and database

1. shutdown normalClose the database normally. 2. shutdown immediateClose the database immediately.Run shutdown immediate in SVRMGRL, and the database is not closed immediately,However, after Oracle executes some cleanup tasks, it closes session

The number of ORACLE connections (sessions) is related to the number of processes in the parameter file. Their relationships are as follows: Sessions = (1.1 * process + 5) However, when we increase the number of processes, the database often

151. CEILING () ORCEIL ()Returns the smallest integer value greater than or equal to the parameter.SELECTCEILING (3.56) FROMBSEMPMS;SELECTCEIL (4.67) FROMBSEMPMS;152. CHAR ()Returns the string representation of the datetime type, String, integer,

PHP + MySQL + Linux has gradually become a classic combination of small web servers. Building and debugging MySQL Databases in Windows is a preferred choice for many website developers. I am a beginner in MySQL in Windows 98. I will summarize the

In SQL Server 2000, the SQL language is the Transact-SQL language. The main components of the Transact-SQL language are as follows: 1. Data Definition Language (DDL)2. Data Manipularion Language (DML)3. Data Control Language (DCL)4. System Stored

ODS is a topic-oriented, integrated, variable, and current collection of detailed data. It is used to support enterprises' demand for instant, operational, and integrated information. It is often used as a data warehouse transition and is also an

Now that DB2 9 has been released, it is time to update pureXML, one of its latest features.®To test the driver. Therefore, a simulated brokerage business environment is established. This environment has the following features: High transaction

I. Databases A database is a collection of data. Whether the database adopts a relational structure or an object-oriented structure, the oracle database stores the data in the data file. Internally, the logical ing of database structure data to

Data Query is one of the most important functions in database operations. Sometimes the performance of database queries is directly related to the database operation efficiency and database selection. I will not talk about the principle below, but I

BKJIA exclusive translation] We know that relational databases do not store data in a hierarchical manner, So how should we obtain data in a hierarchical manner? This article will introduce you to the hierarchical query features provided by Oracle,

-- Before the formal backup, do as follows. -- Copyright statement: -- The reader can copy or modify the content of the backup script without tampering with the author. -- Author: the roles of Xu Yujin's documents: 1. rman_db_all.sh: backs up the

Data structure used for backup and recoveryBoth Oracle and DB2 UDB have a group of components that form backup and recovery mechanisms. The architecture diagram shown in figures 1 and 2 gives an overview of the main components that provide Oracle

I. Composition of installation mediaWe choose INFORMIX-ONLINE and INFORMIX-SQL as the database system development, use and maintenance platform. They store 7 and 4 3.5 inch floppy disks respectively, using the cpio file format.Ii. Installation Steps

There are three main tools used to monitor post-motion of the ONLINE system: System Monitoring Interface SMI), tbstat, and tbcheck. I. System Monitoring Interface SMI) We mainly use SQL commands to operate internal tables/structures in the online

Informix-4GL is a comprehensive fourth-generation application development and generation environment, it has powerful database management functions, flexible and convenient programming, user-friendly interface, has been widely used in UNIX operating

In a dynamic server, CPUVP (cpu virtual processor) is a multi-threaded process that runs on the processor until the following situations occur: 1. CPUVP has no task to do, for example, there is no clue to wait for execution in the ready queue.2. The

The occurrence of deadlocks has an important impact on the system performance and throughput. It has been detected that the deadlock in the management information system is mainly caused by two or more threads logging on to the same table. It takes

Introduction When requirements and requirements for enterprise-level high-performance databases increase, the customer sometimes needs to migrate from the Microsoft Access Jet Engine in the file transfer Server environment to the Microsoft SQL