(Reprinted from www.cnoug.org, original address http://www.cnoug.org/viewthread.php?tid=17741)
Oracle's system is too large. For beginners, there will be some feelings that will not start, everything goes, the result is not good, so I will share the learning experience, I hope that the people who have just started have one for Oracle. Overall awareness, less detours. First, positioning Oracle divided into two blocks, one is developed, one is managing. 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, the learning method is very simple, it is: reading, thinking, writing notes, do experiment, thinking, writing notes to watch the theory, calm down, ask yourself a few, then I have learned and what I want to make a note; when I want to have no or have questions, I do an experiment. I think so, the same, put the results 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 mener has been gone, you are a lot of netizens, especially those who begin schools. When I encounter the problem, I will get the forum. Before asking, have you checked the book, have you studied? Search for 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. Below I talked about the process of my handle, I need to know the official website of Oracle: www.oracle.com There are various versions of Oracle's various versions of the database, application tools and authority. Second, we must also know http://metalink.oracle.com/ This is a partner who bought an Oracle service or Oracle to go in, there are many authoritative solutions and patches. Then there are some famous websites: askTOM.Oracle.com www.orafaq.net, www.dbazine.com. There are many experiences here. I have a problem.
If it is a conceptual problem, you can find TAHITI.Oracle.com, which will give you the most detailed explanation here. If there is any error in the running process. You can go to MetAlink to see. If you want to know the experience of the processing of the transaction. Can go to Asktom. of course. Here is just relative. Third, Oracle's system Oracle's system is very large, to learn it, 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 files: including the necessary information for maintaining and verifying database integrity, for example, control files for identifying data files And redo log files, a database requires at least one control file data file: file redo log files for storage data: Eliminate changes to the database, so that data recovery can be enabled. A database requires at least two redo log file parameter files: Defines the characteristics of the Oracle routine, such as the parameter archive file that adjusts some memory structures in the SGA: is an offline copy of the log file, these copies may be Recovery is necessary in media failure. Password file: Authentication which users have permission to launch and close Oracle routine 2, logical structure (table space, segment, block) table space: is the basic logic structure in the database, a collection of data files. Segment: It is the space area occupied by the object in the database: a larger storage space block for data disposable: Oracle's most basic storage unit, specified 3, memory allocation (SGA and PGA) when establishing a database 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 opposite PGA shared with several processes is only used by one process, and the PGA is assigned to recycle the process when the process is created. 4, background process (Data writing, log write process, system monitoring, process monitoring, checkpoint process, archive process, service process, user process) data write process: responsible for writing data file logs from database buffer cache : Write the change in the log buffer to write online weight log file system monitoring: Check the consistency of the database If necessary, start the database recovery process monitoring when the database is opened: Responsible for cleaning 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: 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 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.
