ORACLE数据库有两类备份方法。第一类为物理备份，该方法实现数据库的完整恢复，但 数据库必须运行在归挡模式下（业务数据库在非归挡模式下运行），且需要极大的外部 存储设备，例如磁带库；第二类备份方式为逻辑备份，业务数据库采用此种方式，此方 法不需要数据库运行在归挡模式下，不但备份简单，而且可以不需要外部存储设备。 数据库逻辑备份方法 ORACLE数据库的逻辑备份分为三种模式：表备份、用户备份和完全备份-ORACLE database there are two types of backup methods. The first category of physical backup, the method to restore the integrity of the database, the database must be running naturalized block mode (Business Database in the naturalization of non-block mode operation), which requires a tremendous amount of external storage devices, such as tape libraries; The second category backup logical way to backup, database mining operations used this way, this method does not run on the database under block mode, the backup is not only simple, but can the need for an external storage devices. Logic database backup method ORACLE database, the logical backup divided into three patterns : Table backup, users backup and complete backup