Basic Introduction and certification of oracle

Source: Internet
Author: User
Tags oracle database installation

1,OracleOfficial preparations recommended by the company

Generally speaking, Oracle has a lot of examination content, and the examination questions are also very detailed, it has a strong requirement on hands-on ability. Therefore, in order to be sure, we must make full preparations in advance, and pay attention to hands-on practices. The following authentication methods are recommended on the official Oracle website for reference.

Oracle University: Instructor guidance and technology-based training provided by Oracle University is the best way to prepare for OCP certification, these courses will lay the foundation for you to pass OCP certification. You can check the course schedule to select the desired preparation method. Your local Oracle university can give you some best suggestions in this regard. You can visit the Oracle website view more information.

Prepare yourself: practical experience is the best way to deepen your understanding of the Oracle exam content. Oracle recommends that you expand your theoretical learning by using new skills and knowledge in your actual work or practice.

Exam Content Checklist: Use the Test Content Checklist to determine all the questions you must prepare. Oracle will constantly update the examination content checklist. Therefore, visit the Oracle website httP: // download the latest examination documents.

Other test tools: the simulated test questions and self-testing software can help you better prepare for the OCP certification test. Oracle and Self Test Software jointly produce high-quality Test Software to help candidates prepare for OCP certification exams. These Software can be purchased through the Oracle website

In fact, the vast majority of Chinese students are preparing for the exam by taking training courses. They not only tutor the knowledge of passing the exam, but also receive other information, including how to register and how to take the exam in the exam room. The official Oracle Introduction above only generally gives you some preliminary education about the preparations. In fact, as we have mentioned earlier, as a huge database system, it is not easy to master Oracle from any angle if you want to master Oracle. Unless you have enough determination and patience to take Oracle as your career path and focus on database technology research, you can truly understand the essence of this complex system. The following discussions will help you gain a preliminary understanding of Oracle.

  2. Basic knowledge of Oracle Database Technology

(1) Oracle databases cover all aspects of database technology.

Although relational databases are not very difficult in terms of principles, it does not take a lot of effort for people with database knowledge to master these principles. In addition, general relational database software, for example, SQL Server is not complex to use, but Oracle is definitely different. As the most successful relational database software in history, Oracle has a wide range of implementation methods and management and maintenance methods. It involves many technical details. It is difficult to understand it from any aspect. If you really want to be proficient in it, it won't work for two or three years. Oracle technical documentation alone is enough to overwhelm you! Specifically, Oracle technology includes the following main aspects: oracle system structure and principle, Oracle database installation and configuration, Oracle database management, Oracle data backup and recovery technology, Oracle performance adjustment, Oracle new product features (Java support, Application servers, time space series, text services, etc) oracle Parallel Server technology, Oracle Data Warehouse Technology, Oracle object type and Object-1 relational model ......

It is no exaggeration to say that any of the above parts is a big question!

(2) Rapid Development of Oracle technology and high correlation of technology.

Although Oracle is only a database system, in actual application, you cannot only face the database itself. For example, if you are managing the network of Oracle databases, you will inevitably encounter problems related to network communication and firewall technology compatibility. Similarly, if you are doing other work, you must also have technical connection problems to solve. What's even worse is that these technologies (including Oracle itself) are growing very fast, making keeping up with them a very hard task.

Fortunately, we do not need to understand all aspects of Oracle at the same time. Oracle provides many application directions. We can choose one of these directions based on our preferences to focus on time and energy, it is not difficult to achieve something in this direction. Since Oracle is currently the world's most important database supplier and the second largest software company, Oracle database technology has been widely used in various fields, so the market demand for Oracle talents is quite large, I cannot find a job after obtaining the OCP certification. In the future, we will be able to apply what we have learned at work and study Oracle databases and related technologies.

  3. How do beginners get started?

If you have said so much, you may have been a little touched, so you may feel helpless in the face of such a giant thing as Oracle. Therefore, we have some suggestions:

(1) find a book on Database principles and master the basic principles of relational databases-if you have never studied such a course.

(2) read the reference books and perform operations on the computer to master the general principles and basic usage of SQL.

(3) buy at least one Oracle entry-level reference book, find a computer with an Oracle version installed (Oracle7.3 or later, preferably Oracle 8), and establish a machine learning environment.

The third point is especially important because I have no practical experience and want to pass the Oracle certification. Or if your budget is sufficient, you can choose to attend the training. When selecting a Training Course, You must select an Oracle-authorized training course to ensure the quality of the training. At the same time, you can enjoy a certain discount during the examination registration.

Unlike many other exams, OCP does not have a reference book in the real sense. What you need to do is to constantly familiarize yourself with Oracle Applications on the computer. The book is just for reference and reference. Fundamentally speaking, Oracle database is a very practical technology, while Oracle certification mainly tests hands-on capabilities. Therefore, there is no practical experience, and only the back-to-back learning materials cannot pass the Oracle certification exam. The following are some common books on the market, which are listed here, hoping to help you.

Beginner: "easy understanding of SQL Structured Query Language", "easy understanding of Oracle Database Development", "Oracle Development Guide", "Oracle beginner's Guide", oracle8 PL/SQL programming.

Advanced: Oracle server technology essence, Oracle8/8i development user manual, Oracle8 copy and recovery manual, and Oracle8 performance optimization and Management Manual.

Many IT professionals do not believe that Oracle DBA has a higher level of gold in addition to technology. Generally, Oracle DBA can design, run, back up, and recover databases, and pay close attention to the whole process of project development. Therefore, a successful Oracle DBA must have both excellent technical skills and excellent coordination capabilities. At the same time, it is necessary to have a deep understanding of the operating system and computer theory. Therefore, DBA must have a bachelor's or master's degree in computer, communication, and business management.

The OCP certification test is a good standard for measuring the mastery of a person's professional technical skills in the Oracle management field, but with the OCP certificate, you do not have to learn the Oracle professional technology. Many people who have obtained OCP certificates and have been in the IT industry for only a few weeks cannot fully understand all concepts of Oracle management.

In fact, the Oracle certificate only allows the employer to know that the applicant has passed the Oracle database technical examination. In fact, Oracle certification is only one of the criteria for measuring a candidate. Other criteria include:

1. excellent communication skills. Oracle DBA usually has to deal with IT technical experts. Therefore, he or she must be able to clearly understand the concept of Oracle for all Oracle Database Access developers or programmers. Sometimes, Oracle DBA is also a manager, so it also requires him to have excellent communication skills in participating in the strategic development plan and database design.

2. Similar degree. Most successful Oracle professionals require a bachelor's degree in computer or information systems. For higher positions, such as Oracle DBA, many employers require a master's degree or MBA in computer science.

3. Some practical experience. This is the most worrying thing for new people who have OCP certificates. Many people with OCP certificates and no work experience complain that they will not have work experience without OCP certificates, and will not have work without work experience. This is a tough issue in the talent market.

4. rich theoretical knowledge of databases. In addition to mastering the technical knowledge required by OCP, a successful Oracle professional must have the software knowledge related to database and database design, this includes the database standardization theory and the object-oriented model using the Unified Modeling Language (UML). Of course, there are other knowledge about database design methods, such as CORBA and J2EE.

In the final analysis, OCP cannot fully measure a person's actual level, but simply provides a way for non-IT industry people to enter the Oracle field.


I. Positioning

Oracle has two major parts: development and management. Development is mainly about writing stored procedures, triggers, and so on, and using Oracle's Develop tool for form. it is a bit similar to a programmer who needs to have strong logical thinking and creative ability. I personally think it will be hard, but it is a problem of youth. management requires a deep understanding of the principles of Oracle databases, it has the ability to perform global operations and close thinking, and has a greater responsibility. Because a small mistake will lead down the entire database, the latter places more emphasis on experience than the former.

Because database management has a major responsibility, few companies are willing to ask a person who has just been in contact with Oracle to manage databases. For young people who have just graduated, they can choose development first, and then transform to database management after some experience. Of course, this depends on the actual situation of individual users.

Ii. Learning Methods

My approach is simple: Reading, thinking, taking notes, experimenting, thinking, and taking notes.

After reading the theoretical things, Let me calm down and think about it. I will ask myself a few more questions and take notes on what I have learned and what I think. I will do experiments when I cannot figure out or have questions, think about how it works. Similarly, write down the experiment results. Thinking and doing experiments aims to gain a deep understanding of this knowledge point. The process of taking notes is also a process of clarifying your own ideas.

The learning process is to make a problem from fuzzy to clear, then from clear to fuzzy. Every change means that you have learned a new knowledge point.

The learning process is also from point to line, from line to network, from network to surface. When the point turns into a line, you will suddenly feel open. When the network reaches the surface, you are the master.

Many netizens, especially beginners, have obtained questions from the Forum. Have you checked the books, studied the books, and searched the Forum before asking? This is called the inertia of thinking. When someone else answers your question, it will make it difficult for you to understand this knowledge point in a short period of time. However, through your own efforts to study it, you will not only gain a deeper understanding of this knowledge point, more importantly, the research process will improve your ability to solve and analyze problems. In general, no matter what you learn, you will not succeed.

Of course, beginners often go to the forum to raise questions when they encounter problems and do not know where to find information. But in my opinion, can I ask others how to analyze this question? Where can I find relevant materials? What is the answer to this question? It is better to teach people to fish than to teach them to fish.

Encountered a problem. If it is a conceptual issue, you can first find Here we will give you the most detailed explanation. If any errors occur during the running process. You can go to metalink. If you want to know the experience of transaction processing. You can go to asktom. Of course. This is just relative.

Iii. Oracle System

Oracle has a huge system. To learn about it, you must first understand the Oracle framework. Here, we will give a brief introduction to the Oracle architecture, so that beginners can have a general understanding of Oracle.

1. Physical Structure (composed of control files, data files, redo log files, parameter files, archive files, and password files)

Control File: contains the necessary information to maintain and verify the integrity of the database. For example, a control file is used to identify data files and redo log files. A database requires at least one control file.

Data File: The file that stores data.

Redo log file: contains the changes made to the database, so that data recovery can be enabled in case of a fault. A database requires at least two redo log files.

Parameter file: defines the features of Oracle routines. For example, it contains parameters for adjusting some memory structures in SGA.

Archive file: an offline copy of the redo log file, which may be necessary to recover from a media failure.

Password File: Authenticate which users have the permission to start and close Oracle routines.

2. Logical Structure (tablespace, segment, partition, block)

Table space: a set of data files in the basic logical structure of the database.

Segment: the space occupied by objects in the database.

ZONE: A large storage space reserved for data at one time.

Block: the most basic storage unit of ORACLE, which is specified when a database is created.

3. Memory Allocation (SGA and PGA)

SGA is the memory area used to store database information, which is shared by database processes. It contains data and control information of the Oracle server. It is allocated in the actual memory of the computer where the Oracle server resides. If the actual memory is insufficient, it is written into the virtual memory.

PGA: contains the data and control information of a single server process or a single background process. The SGA shared with several processes is the opposite. PGA is only used by one process, PGA is allocated when a process is created and recycled when the process is terminated.

4. background processes (Data Writing Process, log writing process, system monitoring, process monitoring, Checkpoint Process, archiving process, service process, and user process)

Data Writing Process: responsible for writing changed data from the database buffer cache to the data file

Log writing process: writes changes in the redo log buffer to online redo log files.

System Monitoring: Checks Database Consistency and starts database recovery when the database is opened if necessary.

Process Monitoring: clears resources when an Oracle process fails.

Checkpoint Process: updates the database status information in control files and data files whenever changes in the buffer cache are permanently recorded in the database.

Archiving process: backs up or archives a full log group during each log switch.

Service Process: User process service.

User process: On the client, the user is responsible for passing the user's SQL statement to the service process and retrieving the query data from the server segment.

5. Oracle routine: The Oracle routine consists of the SGA memory structure and background processes used to manage the database. A routine can only open and use one database at a time.

6. SCN (System ChangeNumber): System Change number, a serial number maintained by the System. It is automatically added when the system needs to be updated. It is an important indicator of maintaining data consistency and sequential recovery in the system.

4. Deep Learning

Management: You can take an examination of the OCP certificate. First, you can have a system for Oracle, and then read Oracle Concepts and Oracle online document. You will have a deeper understanding of the oracle principles, at the same time, you can start some special research such as RMAN, RAS, STATSPACT, DATAGUARD, TUNING, BACKUP & RECOVER, etc.

Development: for Oracle development, after learning about the basic architecture of Oracle, you can focus on PL/SQL and Oracle development tools. PL/SQL mainly includes how to write SQL statements, how to use Oracle functions, How to Write stored procedures, stored functions, and triggers. Oracle's development tools are mainly Oracle's Developer Suite (Oracle Forms Developer and Reports Developer) and learn how to use these tools skillfully.







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