Oracle Certification OCP DBA Research easy to pass the detailed

Finally put OCP DBA's course all finished, tired Ah! Overall Oracle certification is worth the test. I have CCNP, MCSE certificate, but through the DBA examination, feel not only deepened the understanding of modern databases, but also enrich the knowledge structure of computer science. I think, in some ways, Oracle databases even have some operating system capabilities.

Oracle's exams, there are quite a few things to remember, the exam requirements are basically the original command-line approach, rather than the graphical interface operation, so the table name, and the corresponding scripts quite a lot is required to remember, the entire DBA examination, the light book mentioned in the table there are hundreds of of many, I think this is mainly because Oracle has been running on UNIX systems in the past, and there are not many graphical interface software available for use! This also increases the difficulty of the examination correspondingly! The whole exam focus on understanding the concept of the details of the test is not too much, I think the foreign exams are like this! For example, what is the reason for the lock contention? However, the concept of Oracle is a myriad of diverse, countless!

The first SQL is the foundation. This door is not difficult, as long as more than the computer practice, generally no problem, but pl/sql many of the concepts, such as triggers, to find out. If you have the foundation of database development, this course is a piece of cake!

The second door, "Database Management". It is a basic course for Oracle, and it is also a core curriculum that mentions many concepts and methods that are reused in future courses. For example, instance and the corresponding process (pmon,smon,arc0,dbw0, etc.). The physical structure of the database consists of DBF file, control file, redo log file, archive file and so on. The logical composition of the database consists of tablespace,segment,extent,block and so on. What needs to be understood is the basic operation of Oracle, where Oracle reads parameter file's settings in physical memory constructs instance, through the DBWR process, the SGA database The data in the buffer is written to datafile periodically or irregularly, while the SQL instructions are recorded in the Redolog file by the LGWR process, and the system periodically redolog file copy into archive file, the system for transactional needs, The rollback segment was provided so that the read consistence was guaranteed.

The concept of this door is quite numerous, and it is felt that Oracle's storage concepts are quite thin, such as the Pctfree and Pctuse of segment's block, and the concept of row migrate and row chain. It can be seen that Oracle's management of logical and physical objects is very meticulous! Again, SCN is not only stored in control file, but also in the header of DataFile, the SCN is introduced to ensure the coordination and connection between the documents of the system. This door many of the optional parameters of the command is not to be remembered, too much! Also not a test, these parameters in the "performance adjustment" in a detailed introduction of the door! All you have to do is remember the most basic sentences!

The third door, backup and recovery. It helps if you have an understanding of operating system backup and recovery, but Oracle's backup and recovery difficulties lie in the operation of logical objects, for example, the import and export commands are available for table operations. And Rman is the key. Oracle's backup and recovery has a considerable number of classifications, dazzling, with Archivelog and Noarchivelog, full backup and incomplete backup, read-only tablespace backup, media recovery, and so on. This shows that Oracle backup is much more complicated than operating system backups!

In "Network Management" a door, the most practical application is the setting of Net8 and listener. The command used in this door is still very much, for example, in Lsnctr,connection Manger (Cman), Namesctl. Oracle has also made a stack of protocols that correspond to the OSI 7-layer network structure, I think OSI has its own network structure, Cisco also own a set of network structure, now found that Oracle has a similar, I feel ridiculous, more and more feel that the OSI do things for reference only, not be adopted by large manufacturers. I found that Oracle products are doing quite well, and the wonderful thing is that its middle-tier architecture integrates the functions of routers, makes network protocol conversions to Oracle services, and connection concentration is quite reasonable. Oracle Corporation does a name server component that is equivalent to DNS server, similar to Microsoft DNS servers. On network security authorization and authentication, I found that Cisco and Oracle do very similar, for example, both have Kerberos,radius and other authentication applications.

Test this door, if everyone has the knowledge of routing, operating system network knowledge, this door can be said to be quite simple! In other words, for those who have tested Cisco and Microsoft certification, it will be a lot less difficult!

In performance tuning, Oracle's performance tuning cannot be more impressive. Complete range and complete function. The adjustment of share pool is refined to the adjustment of dictionary cache,library Cache,big pool, and the adjustment to physical I/O is more detailed to physical Datafile,dbw0,redo LOG, Lgwr,ckpt,archive,sort,rollback segment and other adjustments. Not to be impressed, the same is the database management system, SQL SERVER 2000,sybase, and even DB2 are not so thin! The SQL statement and application design adjustment, is the most difficult part of the door, if you have a good understanding of the compiler principle, there will be a lot of help. Oracle also specializes in the optimization of multiple CPU systems, such as LATCH,PROCESS,MTS,LRU and other aspects of the parameter settings are related to this. In this door, "database management" in the language learned in the statements of some of the less commonly used options, in this door are described in detail. For example, the build table and the Nosort option in index are designed to reduce the use of sorting. Again, cache options, create and ALTER table are added with cache to place the table in the most-recently-used end of LRU lists to improve performance. The specific usage of the Analyze command mentioned in database management has also been deepened, pointing to tables related to Dba_table, dba_index,index_stats, and so on. The idea that raid is recommended in the operating system to improve disk usage and to put different files on different disks to reduce the read and write disk wait time is mentioned here. There are some methods used by the operating system that provide similar measures in Oracle, such as stripe disks, to improve efficiency. The use of the index mentioned in this gate, rather scientific, such as the establishment of reverse index, as well as index-organization table these are in line with People's optimization thinking! Everyone if the "database management" a lot of basic concepts clear understanding, learning this door will benefit from the Philippines, such as snapshot too old concept, must not ambiguous! For many of the parameters in Init.ora, Oracle thinks it's important to be aware of, for example, the use and setup of Large_pool_size. This door is also important for developer, which enables programmers to focus more on programming from the perspective of improving the efficiency of database programs. From my personal point of view, this course is the most worthy to see, is the concept of allSummary and sublimation.

In my opinion, it would be no problem to pass the OCP DBA exam as long as it takes three months to read a book carefully. Again, it is to read English books directly, so as to save time. There is no translation of the Chinese book on the DBA exam, and there are many mistakes!

From a practical point of view, the actual knowledge that can be used in the work, perhaps also on examination meat capacity of about 30%. But Oracle's methods of implementing these functions represent the ideas and models that many it vendors are actually applying, understanding the principles of Oracle and helping to understand the use of other IT industry products.