Relationship between Oracle database and its basic framework

The following articles mainly involve the basic knowledge of Oracle architecture (Entry level). We all know that if you want to learn Oracle database, you 'd better first understand the basic framework of Oracle. This is the only way to have a general understanding of Oracle databases, which has the role of building a high level.

1. The physical structure consists of control files, data files, redo log files, parameter files, archive files, and password files)

The data in a database is stored in physical files on the disk. When used, the data is transferred to the memory.

The control files, data files, redo log files, trace files, and warning log trace files are database files;

Parameter file (parameter file) password file) is a non-Oracle Database file

1.1 data files: data files that store data. data files typically represent the volume of an Oracle database determined by the disk space and quantity they use.

For performance reasons, each type of data is stored in a corresponding file or a series of files, which are placed on different disks.

Types:

. Data dictionary. data

. Redo data. index

. Temporary data, etc.

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

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

Use of Control Files

The control file directs Oracle to other parts of the database file. When an instance is started, Oracle reads the name and location of the control file from the parameter file. When the database is installed, Oracle opens the control file. When the database is finally opened, Oracle reads the list of data files from the control file and opens each file.

1.3 redo log files:

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

1.4 Trace Files and warning logs (Trace Files and Alert Files)

Every background process running in the instance has a trace file) connected to it. Trace file records the information of major events encountered by background processes.

Warning Log (Alert Log) is a special trace file. Each Oracle database has a trace file that synchronously records database messages and errors.