2012-10-22 11gR2"2DAY DBA"page126-280 & "ADMINISTRATOR'S GUIDE" page1-61

Large object (LOB) columns are used to contain unstructured data (such as text or
streaming video), and can hold terabytes of information. In Oracle Database 11g, you
can use SecureFiles, the next generation LOB data type, which provide high
performance, easier manageability, and full backward compatibility with existing LOB
interfaces. SecureFiles also offer advanced features such as intelligent data
compression, deduplication and transparent encryption. The LOB implementation
available in Oracle Database 10g Release 2 and prior releases is still supported for
backward-compatibility reasons and is now referred to as BasicFiles. If you add a LOB
column to a table, then you can specify whether it should be created as a SecureFile or
a BasicFile. If you do not specify the storage type, then the LOB is created as a
BasicFile to ensure backward compatibility.
此版本的LOB使用了SECUREFILE（之前版本是BASICFILE），可以提供更好的特性。

Synonyms
Because a synonym is simply an alias, it requires no storage other than its
definition in the data dictionary. To reference a synonym in a query, you must have
privileges on the object to which it points. Synonyms themselves cannot be
secured. If you grant object privileges on a synonym to a user, then you are
granting privileges on the object to which the synonym points.
一旦你将SYNONYM的访问权限赋予某个用户，也就相当于你把SYNONYM所指向的对象的权限赋予了此用户，
这在赋权的时候要注意。

 

RMAN Backup Concepts
Incremental Backups of Data Files
RMAN incremental backups copy only those blocks in a data file that change between
backups. A level 0 incremental backup, which copies all blocks in the data file, is used
as a starting point for an incremental backup strategy.
Incremental backups at level 1 copy only images of blocks that have changed since a
previous incremental backup. Level 1 backups can be cumulative, in which case all
blocks changed since the most recent level 0 backup are included, or differential, in
which case only blocks changed since the most recent level 0 or level 1 incremental
backup are included. A typical incremental strategy makes level 1 backups at regular
intervals such as once each day.
简单来说，增量备份就是自上一次全备之后的备份，差分就是自上一次全备或上一次增量的备份。

 

Using the Oracle Suggested Backup Strategy
About the Oracle Suggested Backup Strategy
The Oracle suggested strategy is based on
creating an image copy of your database. The database rolls forward this copy by
using incrementally updated backups. Oracle Enterprise Manager schedules RMAN
backup jobs during the overnight hours.
你可以使用Oracle给你的备份建议，第一天先做一个COPY级别的全备，之后增量备份，当你需要恢复的时候，
你可以把增量备份一起混合进第一天的全备，减少恢复的时间。
脚本类似如下（脚本仅包含将增量备份混合进COPY级别的全备）：

Daily Script:
run {
allocate channel oem_disk_backup device type disk;
recover copy of database with tag 'ORA_OEM_LEVEL_0';
backup incremental level 1 copies=1 for recover of copy with tag
'ORA_OEM_LEVEL_0' database;
}

Deleting Expired Backups
Deleting expired backups removes from the RMAN repository those backups that are
listed as EXPIRED. Expired backups are those found to be inaccessible during a
cross-check. No attempt is made to delete the files containing the backup from disk or
tape; this action updates only the RMAN repository.

Deleting Obsolete Backups
This section explains how to delete obsolete backups, which are those no longer
needed by the configured retention policy. If you use a fast recovery area as your only
disk-based backup destination, then you never have to delete obsolete backups from
disk. The fast recovery area keeps files as specified by the retention policy, and deletes
them only when space is needed.
这里比较一下EXPIRED与OBSOLETE的差别，EXPIRED指的是CROSSCHECK完已不存在磁盘的备份，
PBSOLETE指的是已不在RETENTION POLICY所指定的范围内的备份。

Removing Oracle Database Software
If you want to remove an Oracle software installation, you can use the Deinstallation
tool to completely uninstall the software from your computer.
The Deinstallation Tool (deinstall) is available in Oracle home directories after
installation as $ORACLE_HOME/deinstall/deinstall.
你可以使用Oracle自带的脚本删除Oracle软件。
如下：
To remove an Oracle home from your computer:
1. Execute the Deinstallation tool. The command you enter depends on whether you
are executing the tool from an installed Oracle home or executing the tool after
downloading it from OTN. Do one of the following:
If you are executing the tool from an installed Oracle home, the following is an
example of the commands you would enter:
$ cd /u01/app/oracle
$ product/11.2.0/dbhome_1/deinstall/deinstall
If you are executing the tool after downloading and unzipping the archive file
from OTN, enter the following command (replacing Oracle_home with the full
path name for your Oracle home):
$ deinstall -home Oracle_home

 

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ADMINISTRATOR'S GUIDE

 

Identifying Your Oracle Database Software Release -- Oracle版本号的解释
Release Number Format

 

Checking Your Current Release Number -- 检查当前版本
COL PRODUCT FORMAT A40
COL VERSION FORMAT A15
COL STATUS FORMAT A15
SELECT * FROM PRODUCT_COMPONENT_VERSION;
PRODUCT VERSION STATUS
---------------------------------------- ----------- -----------
NLSRTL 11.2.0.0.1 Production
Oracle Database 11g Enterprise Edition 11.2.0.0.1 Production
PL/SQL 11.2.0.0.1 Production

Administrative Privileges
SYSDBA and SYSOPER  --- SYSDBA与SYSOPER权限的总结