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分类: Oracle

2006-12-19 17:24:56

1219-1. Read-Only Tablespaces

Because read-only tablespaces cannot be modified, and as long as they have not

been made read-write at any point, they do not need repeated backup. Also, if you

need to recover your database, you do not need to recover any read-only

tablespaces, because they could not have been modified.


-2. Transport of Tablespaces Between Databases(表空间传输)

A transportable tablespace lets you move a subset of an Oracle database from one

Oracle database to another on the same platform. You can clone a tablespace and

plug it into another database, copying the tablespace between databases, or you can

unplug a tablespace from one Oracle database and plug it into another Oracle

database, moving the tablespace between databases on the same platform.


Moving data by transporting tablespaces can be orders of magnitude faster than

either export/import or unload/load of the same data, because transporting a

tablespace involves only copying datafiles and integrating the tablespace metadata.

When you transport tablespaces you can also move index data, so you do not have

to rebuild the indexes after importing or loading the table data.


Note: You can transport tablespaces only between Oracle databases that use the same character set and that run on compatible platforms from the same hardware vendor.


-3How to Move or Copy a Tablespace to Another Database

To move or copy a set of tablespaces, you must make the tablespaces read-only,

copy the datafiles of these tablespaces, and use export/import to move the database

information (metadata) stored in the data dictionary. Both the datafiles and the

metadata export file must be copied to the target database. The transport of these

files can be done using any facility for copying flat files, such as the operating

system copying facility, ftp, or publishing on CDs.


-4.Oracle allocates space for the data associated with a schema object in one or more datafiles of a tablespace.Therefore, a schema object can span one or more datafiles. Unless table striping is used (where data is spread across more than one disk), the database administrator and end users cannot control which datafile stores a schema object.

Oracle给在一个表空间的一个或多个数据文件的schema object的所有数据分配空间,schema object能够跨越数据文件。Unless table striping is used (where data is spread across more than one disk)如何理解?数据库管理员和最终用户不能控制那个数据文件来存储那个schema object

-5.Control Files Overview

.A control file is updated continuously by Oracle during database use, so it must be available for writing whenever the database is open.


-6. Control File Contents

Among other things, a control file contains information such as:

1Datafile offline ranges

2Backup set and backup piece information

3The current log sequence number






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