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oracle-managed files (35)

原创 Oracle 作者:tsinglee 时间:2007-09-25 17:37:58 0 删除 编辑

Oracle-managed files eliminate the need for you, the DBA, to directly manage the
operating system files comprising an Oracle database. You specify operations in terms
of database objects rather than filenames. Oracle internally uses standard file system
interfaces to create and delete files as needed for the following database structures:
1 Tablespaces
2 Redo log files
3 Control files
Through initialization parameters, you specify the file system directory to be used for
a particular type of file. Oracle then ensures that a unique file, an Oracle-managed file,
is created and deleted when no longer needed.

initialization parameters : db_create_file_dest
comprise
包含, 由...组成

再转一篇文章

为了理解OMF是如何工作的,让我们首先定义一个叫着DB_CTEATE_FILE_DEST的新参数。

alter system set db_create_file_dest='/u01/oradata/PROD';

一旦设置好了DB_CTEATE_FILE_DEST参数,我们就可以创建表空间而无须指定文件名。

createtablespace
omf1
datafile size 100m
locally managed;

文件创建之后,Oracle就可以分配和命名这些文件。Oracle OMF使用如下的命名转换惯例。默认的文件大小为100M,并按如下格式命名:

where
%u is a unique 8 digit code
%g is the log file group number
%t is the tablespace name

Controlfiles ora_%u.ctl
Redo Log Files ora_%g_%u.log
Datafiles ora_%t_%u.dbf
Temporary Datafilesora_%t_%u.tmp

Oracle9i OMF工具还有一个新的警告日志消息(alert log message),它用来告诉我们OMF数据文件何时发生了改动。下面是关于警告日志的一个例子。

Fri Mar 23 01:44:46 2001
CREATE TABLESPACE omf1 DATAFILE SIZE 10M AUTOEXTEND OFF
Fri Mar 23 01:44:47 2001
Created Oracle managed file /databases/ed25/OMF1/ora_omf1_xcp6rg84.dbf
Completed: CREATE TABLESPACE omf1 DATAFILE SIZE 10M AUTOEXTE
Fri Mar 23 01:45:45 2001
drop tablespace omf1
Fri Mar 23 01:45:45 2001
Deleted Oracle managed file /databases/ed25/OMF1/ora_omf_xcp6rg84.dbf
Completed: drop tablespace omf1

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