Oracle Database Administration: The Essential Refe

Export/import

The Export utility, known as EXP, takes a logical backup of the database. EXP writes, in a proprietary format, all the SQL commands necessary to recreate the database objects as well as insert all the data. The companion Import utility, IMP, reads this file and executes all the statements. You can export at the database level, schema level, or table level, and you can import all or a portion of the export file.

Export is the only backup utility that allows you to recreate a single table. In addition, Export is the only backup technique that will allow you to recover your database to a different hardware platform running a different operating system—and perhaps even a different version of Oracle. This utility can be used to recover from both user and processing errors. For information on the use of IMP and EXP, see Chapter 4, and Chapter 16.

Warning

In a relational database, it may not be possible (or make sense) to recover only one table. Multiple tables may need to be recovered in order to maintain referential integrity. Also, recovery can only be performed to the time of the export. Any changes made to the database after the export will be lost.