First, positioning
Oracle is divided into two blocks, one is development, one is management. The development is mainly written in the stored procedure, what is the trigger, and it is forming FORM with Oracle's developing tool. It is a bit similar to the programmer, you need to have strong logical thinking and creativity, personal feeling more hard, is youthful J; management requires a deep understanding of the principle of Oracle database, there is a global manipulation ability and close thinking The responsibility is large, because a small mistake will drop the entire database, relative to the former, the latter value more empirical.
Because database management is responsible, it is willing to ask a person who has just reached Oracle to manage the database. For young people who have just graduated, you can choose to do development, have a certain degree of experience, to do the management of the database. Of course, this is still to see the actual situation of people.
Second, learning method
My method is very simple, it is: reading, thinking, writing notes, do experiment, thinking, writing notes
After reading the theory, I will calm down, ask yourself a few, then do a notes you learned and what you want; when you want to have questions, you will do experiments, think about it. How can it be like this, the same, a record of the experiment. Thinking and experimenting is to understand this knowledge point for in-depth understanding. The process of doing notes is also a process of clarifying his own ideas.
The process of learning is to make a problem by blurring to clear, and then clear to the fuzzy process. Each change represents you have learned a new knowledge point.
The process of learning is also from point-to-line, from the line to the network, from the network to face. When you turn to the line, you will always have a sense of cheerful feelings. When the mesh is facing, you are a master.
Many netizens, especially those who begin schools, I got the forum, I got the forum. Before asking, have you checked the book, have you studied, have you search for a forum? This is called thinking inert. From others to answer your questions, let you understand this knowledge point in a short time, but through your own efforts to study it, not only know more about this knowledge point, but more importantly, it is studying The process will improve your ability to solve problems and analyze problems. In general, there is no study attitude of drilling, no matter what something, it will not succeed.
Of course, there are many people in the beginner because they have encountered problems, and they don't know where to find information will be issued. But I think that when you ask questions, can I ask someone how to analyze this problem? Where can I find related information? Instead of this question, what is the answer? It is better to teach people to fish with fish.
Third, Oracle system
Oracle's system is very large, to learn it, first understand the Oracle's 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 start and close Oracle routines 2, logical structure (table space, segments, districts, blocks)
Table space: It is the basic logical structure in the database, a collection of data files.
Segment: It is the space occupied in the database
District: Yes, a larger storage space for data disposable
Block: Oracle's most basic storage unit, specified when establishing a 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 for a single server process or a single background process, and the SGA positive and opposite PGA shared with several processes is only used by a process, and the PGA is assigned when creating the process. Recycling
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 data files from database buffer cache cache
Log write procedures: Changes in log buffers will be written to log files online
System monitoring: Check the consistency of the database If necessary, start the database recovery when the database is turned on.
Process monitoring: Clean up resources when an Oracle process fails
Checkpoint Process: Update database status information in the data file when the change in the database is permanently recorded in the database whenever the change in the buffer cache is permanently recorded.
Archive Process: Back up or archive full log groups in each log switching
Service Process: 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 Change Number): System change number, a serial number maintained inside 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
Oracle8i Backup Recovery Manual
Oracle8 Advanced Management and Optimization
Oracle8i PLSQL program design
Oracle8 Database Administrator Manual
Oracle9 Statspack High Performance Adjustment
The above books are all published by Machinery Industry Press.
There is also an OCP's teaching book.
Introduce several websites
Http://tahiti.oracle.com Oracle's official documentation
Http://metalink.oracle.com/ Oracle Technical Support Website. 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
