Author: selina33 dispatch time: 2005.01.31 Third, the system Oracle's Oracle system is very large, have to learn it, we must first understand the Oracle framework. Here, briefly tell the Oracle architecture, so that beginners have a holistic understanding of Oracle.
1. Physical structure (consisting of control files, data files, redo log files, parameter files, archive files, password files)
Control file: The necessary information containing maintenance and verify database integrity, for example, the control file is used to identify data files and redo log files, and a database requires at least one control file.
Data file: files that store data.
Redo the log file: The change record that is made to the database, so that the data recovery can be enabled. A database requires at least two redo log files.
Parameter file: Define the characteristics of the Oracle routine, for example it contains parameters that adjust some memory structure in SGA.
Archive file: It is an offline copy of the log file, which may be necessary to recover from the failure of the media.
Password file: Certified which users have permission to launch and close the Oracle routine.
2, logical structure (table space, segment, zone, block)
Table space: It is the basic logical structure in the database, a collection of data files. Segment: It is the space occupied by the object in the database. Zone: is a larger storage space for data one-time. Block: Oracle's most basic storage unit, specified when establishing the database.
3, memory allocation (SGA and PGA)
SGA: is a memory area for storing database information, which is shared by a database process. It contains data and control information of the Oracle server, which is assigned in the actual memory of the computer resides in the Oracle server, and if the actual memory is not written in virtual memory.
PGA: Contains data and control information of a single server process or a single background process, and the SGA positive and opposite PGA shared with several processes is only used by one process, and the PGA is assigned when the process is created during termination process.
4, background process (data writing process, log write process, system monitoring, process monitoring, checkpoint process, archiving process, service process, user process)
Data Write Process: Responsible for writing the data from the database buffer cache to write data file log: Write the change in the log buffer to write online weight log file system monitoring: Check the consistency of the database If necessary The recovery process monitoring of the database will also be launched when the database is opened: It is responsible for cleaning the resource checkpoint process when an ORACLE process fails: Database status information in the file. Archive Process: A full log group is backed up or archived at each log switch: User Process Service. User Process: At the client, it is responsible for passing the user's SQL statement to the service process and collects query data from the server segment.
5, Oracle routines: Oracle routines consist of SGA memory structure and composed of background processes for managing databases. The routine can only open and use a database at a time.
6, SCN (System Changenumber): System change number, a serial number maintained by the system. Automatic increase when the system needs to be updated, and he is an important sign for consistency and sequential recovery in the system.
Fourth, in-depth study
Manage: You can test the OCP certificate, there is a systematic study of Oracle, then look at Oracle Concepts, Oracle Online Document, with more in-depth understanding of the principle of Oracle, and start some topics, such as: RMAN, RAS, Statspact, DataGuard, Tuning, Backup & Recover, etc. Development: For Oracle development, you can focus on the part of PL / SQL and Oracle's development tools after understanding Oracle's basic architecture. PL / SQL mainly includes how to write SQL statements, how to use Oracle itself, how to write store procedures, storage functions, triggers, and more. Oracle's development tools are mainly Oracle's own developer Suite (Oracle Forms Developer and Reports Developer), learn how to skilful use of these tools.
Introduce several Oracle entlets giving a good book
Oracle official document: "Concept" talked about Oracle's system and concept, which is very suitable for beginners. OCP's teaching book, that is, Study Guide (SG). Oracle8i Backup Recovery Manual Oracle8 Advanced Management and Optimization Oracle8i PLSQL Program Design Oracle8 Database Administrator Manual All books are all published by Machinery Press.
Introduce several websites
Http://tahiti.oracle.com Oracle's official documentation
Now http://www.oracle.com.cn/onlinedoc/index.htm also has official documentation, fast speed
Http://metalink.Oracle.com/, the technical support website for Httom/, Oracle. You need to buy an Oracle service to have an account, in order to log in, have a lot of Knowledge Base, a lot of questions to solve the experience.
Http://www.oracle.com Oracle's official website, you can download software, official documentation and get the latest news
Http://www.dbazine.com/ Oracle Magazine
http://asktom.oracle.com
http://www.orafaq.net/
http://www.ixora.com.au/
http://www.racle-base.com
http://www.dba-oracle.com/oracle_links.htm
