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關(guān)于OCP的小知識(shí)點(diǎn)，實(shí)例受限啟動(dòng)，實(shí)例啟動(dòng)的知識(shí)點(diǎn)很多，也是OCP學(xué)習(xí)的重點(diǎn)，需要多看官方文檔和多做測(cè)試。
Restricting Access to an Instance at Startup
--實(shí)例啟動(dòng)限制
You can start an instance, and optionally mount and open a database, in restricted mode so that the instance is available only to administrative personnel (not general database users).
Use this mode of instance startup when you must accomplish one of the following tasks:
--實(shí)例啟動(dòng)限制模式適用的場(chǎng)景，一定是我們不希望其他連接訪問數(shù)據(jù)，對(duì)數(shù)據(jù)庫數(shù)據(jù)進(jìn)行改動(dòng)，數(shù)據(jù)備份，loader，臨時(shí)阻止已經(jīng)升級(jí)遷移會(huì)常常使用到。
?Perform an export or import of data
?Perform a data load (with SQL*Loader)
?Temporarily prevent typical users from using data
?Perform certain migration or upgrade operations
Typically, all users with the CREATE SESSION system privilege can connect to an open database. Opening a database in restricted mode allows database access only to users with both the CREATE SESSION and RESTRICTED SESSION system privilege. Only database administrators should have the RESTRICTED SESSION system privilege. Further, when the instance is in restricted mode, a database administrator cannot access the instance remotely through an Oracle Net listener, but can only access the instance locally from the system that the instance is running on.
The following command starts an instance (and mounts and opens the database) in restricted mode:
小實(shí)驗(yàn)：
[root@11g-ocp ~]# su - oracle
<11g-ocp:orcl:/home/oracle>$sqlplus / as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Wed Dec 12 18:12:11 2018
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP and Real Application Testing options
SQL> startup restrict force
ORACLE instance started.
--限制模式啟動(dòng)
Total System Global Area 1870647296 bytes
Fixed Size 2254304 bytes
Variable Size 503319072 bytes
Database Buffers 1358954496 bytes
Redo Buffers 6119424 bytes
Database mounted.
Database opened.
SQL> drop user roidba;
--刪除測(cè)試用戶
User dropped.
SQL> create user roidba identified by roidba;
--創(chuàng)建測(cè)試用戶
User created.
SQL> grant connect,resource to roidba;
--授權(quán)訪問
Grant succeeded.
SQL> conn roidba/roidba;
ERROR:
ORA-01035: ORACLE only available to users with RESTRICTED SESSION privilege
--登陸報(bào)錯(cuò)，缺少系統(tǒng)權(quán)限r(nóng)estricted session
Warning: You are no longer connected to ORACLE.
SQL> conn / as sysdba
Connected.
SQL> grant restricted session to roidba;
Grant succeeded.
--授予系統(tǒng)權(quán)限r(nóng)estricted session
SQL> conn roidba/roidba
Connected.
--使用roidba連接數(shù)據(jù)庫，成功
SQL> conn / as sysdba
Connected.
SQL> revoke restricted session from roidba;
--收回權(quán)限
Revoke succeeded.
SQL> alter system disable restricted session;
--取消限制
System altered.
SQL> conn roidba/roidba;
--收回權(quán)限和取消限制抵消，可以繼續(xù)登陸
Connected.
SQL>
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