Oracle Database files

Files in oracle database

In this article, we can see the important files in the oracle database. Oracle database is a popular RDBMS database. It has some important files in which the database runs.

• Control File
• Parameter File
• Data File
• Redo logs
• Archive Logs
• Alert log
• Trace File

Control File : 

In Oracle database, the control file is the most important file which contains the information about the database. It contains information like

• Database name
• Number of datafiles
• Location of all the datafiles
• Last SCN Number
• Date of the database created.

So it is always good to keep the control file multiplexed.  And also this helps the database to open as consistent with data.

Parameter File:

The parameter file is the important file in oracle database Which contains the information about the SGA and PGA memory size.  And the location of the control files. Without the parameter file, we cant startup the database. The parameter file is also called as 'init.ora'.

Data file:

These files are used to store data physically on disks Which is logical present as tablespace in oracle database.

Redo logs:

These files are used to store the logs which record every transaction happening in the oracle database. These files will work in a circular fashion if a group gets filled another group will Come online. The group which currently records the transactions is called the online redo log. and the other is called offline redo logs.

Redo logs and Archive logs help to restore the database if the database is unexpectedly crashed with the help of the control file. These files are managed in a group. A redo log group contains 2 files and we always manage two or more groups and the size is based on the number of transactions happening in the database.

There are more things about the redo log. We will learn more about this later.

Archive Logs:

These files are the backup of the redo log files. As we have seen redo log will work in a circular fashion if a group comes to offline the archive log writer takes the backup of that group and stores it that is called the archive logs.

Backup File:

As we know backup is important in every working environment. However, we can able to restore the database with redo logs and archive logs with the current transactions. We should have 

Alert Logs:

This file is automatically generated by the oracle database. In this file, we can find the errors that happened in the oracle database. 

Trace files:

These files are also generated by Oracle database in some conditions like When the database id crashed and if a session gets failure.

And will post more information about each file in the next article.