How does Oracle perform database backups?

There are several ways to backup an Oracle database, including:

1. Cold Backup: This backup method involves directly backing up the database files while the database is offline. Although simple and reliable, it requires the database service to be temporarily paused.
2. Hot Backup: A type of backup where the database is backed up while it is still running, using online backup tools provided by Oracle such as RMAN (Recovery Manager). This method does not require the database service to be paused, but special settings need to be applied to the database to support online backups.
3. To export a database (Data Pump), you can use Oracle’s provided export tools like expdp (for Oracle 11g and above) or exp (for Oracle 10g and below) to export data and objects into portable data files. This backup method allows you to export the entire database or specific tables, tablespaces, etc., but does not include the database’s physical files.
4. Database mirroring is the process of duplicating a database to another physical location as a backup. This method allows for real-time synchronization of the mirrored database and the primary database to ensure data integrity and timeliness.

No matter which backup method is chosen, regular backups are necessary and the backup files should be stored in a secure location for recovery in case of failure or data loss. Additionally, the backup strategy should be adjusted and optimized based on business needs and the frequency of data changes.