General framework of Oracle, Oracle framework

General framework of Oracle, Oracle framework

The physical structure of Oracle includes parameter files, control files, data files, redo log files, archive files, and password files.

1.1 parameter file

This includes a large number of settings that affect the functions of Oracle database instances, as shown in the following settings:

Locating Database Control Files

The amount of memory that Oracle uses to cache data read from the disk

Select the default optimizer.

　　
Perform two important functions related to database files:

Specify the control file for the database

Specify the log archiving target for the database

1.2 Control File

Contains 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.

Oracle can use multiple control files, that is, maintain multiple identical control files at the same time to prevent database faults caused by Control File Corruption.

Control File Content:

Database Name

Tablespace Information

Names and locations of all data files

Names and locations of all redo log files

Current Log serial number

Checkpoint Information

Redo log and archive current status information

Control File Usage process:

When an instance is to be started, oracle reads the name and location of the control file from the parameter file, opens the control file when the database is created, and opens the database, read the list of data files from the control file and open each file.

1.3 Data Files

A data file only belongs to one database. One or more data files form a logical structure-tablespace in the database.

When necessary, the data in the data file is read through database operations and cached in the oracle memory.

1.4 redo log files

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 to form the redo log of the database.

1.5 archive files

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

1.6 Password File

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

Can anyone tell me what is the main component of Oracle?

ORACLE is a portable database that can be used on every platform. It is called a cross-platform feature. There are also slight differences in different operating systems. For example, in UNIX/LINUX, ORACLE is implemented by multiple processes, and every major function is a process. In Windows, it is a single process, but it contains multiple threads. However, from the perspective of the overall architecture, ORACLE is the same on different platforms, such as memory structure, background process, and data storage.
A running ORACLE Database can be considered as an oracle server, which is composed of a Database and an Instance, generally, an oracle server contains an instance and a corresponding database. However, in special cases, such as 8i OPS, 9i RAC, one database in one SERVER can correspond to multiple instances.
A collection of physical files (data files, control files, online logs, etc.) or a logical structure (tablespace, segment, etc.) corresponding to it is called a database. In short, is a series of physical files related to the disk. ORACLE Memory Structures and background processes are used as database instances. A single instance can only be installed (mounted) and opened (Open) on a single database, and is responsible for database operations and user interaction.
The Oracle memory structure mainly consists of the shared memory Area and non-shared memory Area. The shared memory Area mainly includes the SGA (System Global Area), and the non-shared memory Area mainly consists of the PGA (Program Global Area.
The background process is an Oracle program used to manage database read/write, recovery, and monitoring. Server Process communicates with user process and exchanges data with user process. On Unix machines, the Oracle background process is relative to the operating system process. That is to say, an Oracle background process starts an operating system process. On Windows machines, the Oracle background process is relative to the operating system thread, open the task manager and we can only see one ORACLE..

To what extent does oracle learn to find a job?

For java software development, beginners are required for the SSH framework. The database is almost enough and lacks practical experience.
If a database works unilaterally, PL programming, basic database references (including timers, custom methods, stored procedures, views, etc.), and database efficiency optimization (such as Table Partitioning technology in oracle ). The most important thing is to be proficient in database operations (such as windows, aix, and LINUX) in different systems. vi must be proficient in operations...
Hope to help you ~