Oracle adopts the object-relational theorem to provide scalable and easily manageable mechanism to support all kinds of information technology need. There are many possible career paths available in the job market in various industries that you can choose related to Oracle knowledge.
I will introduce the information and knowledge I personally have, and try to help you to learn Oracle as a whole package by the assuming role of being a DBA (database administrator) per your interest and benefit.
Oracle Architectural Component
Oracle server: The oracle server, by concept, is the Oracle DBMS server, which managing user’s processes, data transactions, data files, and all the related jobs/objects. Physically, Oracle server consisted of both Oracle instance and Oracle data files.
Oracle Instance: The bunch of Oracle server processes, which are the processors in oracle mechanism manipulating all the data processing and transactions; and the memory components, which stored the data and meta data in the processing and database.
Database: Conceptually, the database we are talking about usually refer to the data files in the Oracle, which including data files, control files, and redo log files.
Oracle Instances includes two categories of components:
1) Processses: the processes which handle all the transactions and data processing, which include PMON, SMON, DBW, LGW, CKPT, and others, ex: ARC.
2) Memory components: the momory segments and semaphores in the OS, which contain the meta dataof oracle components, the data being processed and temporary data. It includes DB Cache, Shared Pool, redo log Buffer, Java Pool, Large Pool. SGA (System global area) is the name refer to the group of the memory segments.
Other Oracle components:
- PGA (Program Global Area): refers to the server process from the application or clients, when they established a connection sesstion to the database server.
- Parameter files, including pfile and spfile. This is a very initial file a DBA needs to setup when building an Oracle database. The Pfile is the text based parameter file, which you used to specify the Oracle database parameter. The spfile is the server based parameter file, which is binary based. You need to login to the Oracle instance to make the parameter change.
- Password file, which contain the password inforamtion to allow the remote connection for sysdba privilege login.
- Archived log files, the archived redo log files, which contain the transaction history for recovery purpose. This is required for full recovery, so it's used for most production systems.
More detail will be discussed for each component later on.
Database: Conceptually, the database we are talking about usually refer to the data files in the Oracle, which including data files, control files, and redo log files.
Oracle Instances includes two categories of components:
1) Processses: the processes which handle all the transactions and data processing, which include PMON, SMON, DBW, LGW, CKPT, and others, ex: ARC.
2) Memory components: the momory segments and semaphores in the OS, which contain the meta dataof oracle components, the data being processed and temporary data. It includes DB Cache, Shared Pool, redo log Buffer, Java Pool, Large Pool. SGA (System global area) is the name refer to the group of the memory segments.
Other Oracle components:
- PGA (Program Global Area): refers to the server process from the application or clients, when they established a connection sesstion to the database server.
- Parameter files, including pfile and spfile. This is a very initial file a DBA needs to setup when building an Oracle database. The Pfile is the text based parameter file, which you used to specify the Oracle database parameter. The spfile is the server based parameter file, which is binary based. You need to login to the Oracle instance to make the parameter change.
- Password file, which contain the password inforamtion to allow the remote connection for sysdba privilege login.
- Archived log files, the archived redo log files, which contain the transaction history for recovery purpose. This is required for full recovery, so it's used for most production systems.
More detail will be discussed for each component later on.
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