read only tablespace

最新推荐文章于 2025-10-21 22:09:11 发布

原创最新推荐文章于 2025-10-21 22:09:11 发布 · 463 阅读

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#dictionary #table #database #file #user

本文介绍只读表空间的使用方法及其目的，包括防止大型静态数据库部分的备份与恢复需求，保护历史数据不被修改等。同时讨论了只读表空间的一些限制条件，例如不能创建或更改对象，以及如何通过数据字典更新文件描述。

Using Read -Only Tablespaces

Making a tablespace read -only prevents write operations on the datafiles in the tablespace . The primary purpose of read -only tablespaces is to eliminate the need to perform backup and recovery of large, static portions of a database. Read -only tablespaces also provide a way to protecting historical data so that users cannot modify it. Making a tablespace read -only prevents updates on all tables in the tablespace , regardless of a user's update privilege level.

Note:

Making a tablespace read -only cannot in itself be used to satisfy archiving or data publishing requirements, because the tablespace can only be brought online in the database in which it was created. However, you can meet such requirements by using the transportable tablespace feature, as described in "Transporting Tablespaces Between Databases" .

You can drop items, such as tables or indexes, from a read -only tablespace , but you cannot create or alter objects in a read -only tablespace . You can execute statements that update the file description in the data dictionary, such as ALTER TABLE ... ADD or ALTER TABLE ... MODIFY , but you will not be able to utilize the new description until the tablespace is made read /write.

Read -only tablespaces can be transported to other databases. And, since read -only tablespaces can never be updated, they can reside on CD-ROM or WORM (Write Once-Read Many) devices.

The following topics are discussed in this section: