Oracle Database Backup and Recovery
Effective backup and recovery strategies are essential for ensuring the availability and integrity of data in an Oracle Database 12c environment. This section will cover key concepts related to Oracle Database backup and recovery.
1. Physical Backups
Physical backups involve copying the physical files that make up the database, such as datafiles, control files, and redo log files. These backups are essential for recovering the database in case of a physical failure, such as disk corruption or hardware failure.
Example: Think of physical backups as making a photocopy of all the pages in a book. If the original book is damaged, you can use the photocopies to recreate the book.
2. Logical Backups
Logical backups involve exporting the logical structure and data of the database, such as tables, views, and indexes, into a file that can be imported later. Logical backups are useful for transferring data between databases or for archiving purposes.
Example: Consider logical backups as creating a detailed outline of a book, including all the chapters and sections. This outline can be used to recreate the book's content in another location.
3. Full Database Recovery
Full database recovery involves restoring the entire database from a complete backup and applying all necessary redo log files to bring the database to its most recent state. This type of recovery is typically used after a catastrophic failure, such as a complete loss of the database files.
Example: Imagine full database recovery as rebuilding a house from the ground up using blueprints and construction logs. The blueprints (backup) provide the structure, and the logs (redo logs) ensure everything is up to date.
4. Point-in-Time Recovery
Point-in-Time Recovery (PITR) allows you to restore the database to a specific point in time, rather than just the most recent backup. This is achieved by using archived redo logs to roll forward the database to the desired time. PITR is useful for recovering from user errors or data corruption that occurred after the last backup.
Example: Think of PITR as rewinding a movie to a specific scene and then playing it forward to that point. The movie (database) is restored to the desired scene (point in time) using the rewind and play functions (archived redo logs).
By understanding and implementing these key concepts of Oracle Database backup and recovery, you can ensure the availability, integrity, and recoverability of your database, safeguarding your data against various types of failures.