Oracle's broad framework

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

1.1 Parameter file

Includes a number of settings that affect the capabilities of the Oracle DB instance, such as the following:

fixed position of database control files

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

The selection of the default optimizer.

　　
is related to the database file and performs two important functions :

To indicate a control file for a database

Indicate the destination of the archive log for the database

1.2 Control files

Contains necessary information to maintain and verify database integrity, for example, control files are used to identify data files and redo log files, and a database requires at least one control file.

Oracle can use multiple control files to maintain multiple identical control files at the same time to prevent database failures caused by file corruption.

Control file Content:

Database name

Table Space Information

Name and location of all data files

Name and location of all redo log files

The current log sequence number

Checkpoint Information

About the current status information for redo logs and archives

To control the file usage process:

When an instance is started, Oracle reads the name and location of the control file from the parameter file, then opens the control file when the database is established, and, when the database is opened, reads the list of data files from the control file and opens each file.

1.3 Data files

A data file belongs to only one database, and one or more data files form a logical structure in the database-table space.

When needed, the data in the data file is read through the database operation and cached in Oracle's memory.

1.4 Redo Log Files

Redo log files: Contains a record of the changes made to the database so that data recovery can be enabled in the event of a failure. A database requires at least two redo log files that make up the database's redo log.

1.5 Archive files

is an offline copy of the redo log files, which may be necessary to recover from media failure.

1.6 Password file

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

Oracle's broad framework