在Oracle 816 以后的版本中,Oracle提供了一个包
BMS_BACKUP_RESTORE.
DBMS_BACKUP_RESTORE 包是由dbmsbkrs.sql 和 prvtbkrs.plb 这两个脚本创建的.catproc.sql 脚本运行
后会调用这两个包.所以是每个数据库都有的这个包是Oracle服务器和操作系统之间IO操作的接口.由恢复管理器直接调用。
由此可见，我们可以在数据库nomount 情况下调用这些package ,来达到我们的恢复目的。
在dbmsbkrs.sql 和prvtbkrs.plb 这两个脚本中有详细的说明文档，就不一一加以翻译了。
关键的内容有：
FUNCTION deviceAllocate( type IN varchar2 default NULL
,name IN varchar2 default NULL
,ident IN varchar2 default NULL
,noio IN boolean default FALSE
,params IN varchar2 default NULL )
RETURN varchar2;
-- Describe the device to be used for sequential I/O. For device types where
-- only one process at a time can use a device, this call allocates a device
-- for exclusive use by this session. The device remains allocated until
-- deviceDeallocate is called or session termination. The device can be used
-- both for creating and restoring backups.
--
-- Specifying a device allocates a context that exists until the session
-- terminates or deviceDeallocate is called. Only one device can be specified
-- at a time for a particular session. Thus deviceDeallocate must be called
-- before a different device can be specified. This is not a limitation since
-- a session can only read or write one backup at a time.
--
-- The other major effect of allocating a device is to specify the name space
-- for the backup handles (file names). The handle for a sequential file does
-- not necessarily define the type of device used to write the file. Thus it
-- is necessary to specify the device type in order to interpret the file
-- handle. The NULL device type is defined for all systems. It is the file
-- system supplied by the operating system. The sequential file handles are
-- thus normal file names.
--
-- A device can be specified either by name or by type.
-- If the type is specified but not the name, the system picks an
-- available device of that type.
-- If the name is specified but not the type, the type is determined
-- from the device.
-- If neither the type or the name is given, the backups are files in
-- the operating system file system.
-- Note that some types of devices, optical disks for example, can be shared
-- by many processes, and thus do not really require allocation of the device
-- itself. However we do need to allocate the context for accessing the
-- device, and we do need to know the device type for proper interpretation
-- of the file handle. Thus it is always necessary to make the device
-- allocation call before making most other calls in this package.
--
-- Input parameters:
-- type
-- If specified, this gives the type of device to use for sequential
-- I/O. The allowed types are port specific. For example a port may
-- support the type "TAPE" which is implemented via the Oracle tape
-- API. If no type is specified, it may be implied by specifying a
-- particular device name to allocate. The type should be allowed to
-- default to NULL if operating system files are to be used.
--
-- name
-- If specified, this names a particular piece of hardware to use for
-- accessing sequential files. If not specified, any available
-- device of the correct type will be allocated. If the device cannot
-- be shared, it is allocated to this session for exclusive use.
-- The name should be allowed to default to NULL if operating system
-- files are to be used.
--
-- ident
-- This is the users identifier that he uses to name this device. It
-- is only used to report the status of this session via
-- dbms_application_info. This value will be placed in the CLIENT_INFO
-- column of the V$SESSION table, in the row corresponding to the
-- session in which the device was allocated. This value can also
-- be queried with the dbms_application_info.read_client_info procedure.
--
-- noio
-- If TRUE, the device will not be used for doing any I/O. This allows
-- the specification of a device type for deleting sequential files
-- without actually allocating a piece of hardware. An allocation for
-- noio can also be used for issuing device commands. Note that some
-- commands may actually require a physical device and thus will get
-- an error if the allocate was done with noio set to TRUE.
--
-- params
-- This string is simply passed to the device allocate OSD. It is
-- completely port and device specific.
--
-- Returns:
-- It returns a valid device type. This is the type that should be
-- allocated to access the same sequential files at a later date. Note
-- that this might not be exactly the same value as the input string.
-- The allocate OSD may do some translation of the type passed in. The
-- return value is NULL when using operating system files.
PROCEDURE restoreControlfileTo(cfname IN varchar2);
-- This copies the controlfile from the backup set to an operating system
-- file. If the database is mounted, the name must NOT match any of the
-- current controlfiles.
--
-- Input parameters:
-- cfname
-- Name of file to create or overwrite with the controlfile from the
-- backup set.
PROCEDURE restoreDataFileTo( dfnumber IN binary_integer
,toname IN varchar2 default NULL);
--
-- restoreDataFileTo creates the output file from a complete backup in the
-- backup set.
等等。
