oracle 10G Drop Database

Oracle 10g 增加了drop database 命令，这样我们删除数据库会方便很多。

不过DROP DATABASE还是有一定的限制条件的：

SQL> conn / as sysdba
Connected.
SQL> drop database;
drop database
*
ERROR at line 1:
ORA-01586: database must be mounted EXCLUSIVE and not open for this operation


SQL> alter database close;

Database altered.

SQL> drop database;
drop database
*
ERROR at line 1:
ORA-12719: operation requires database is in RESTRICTED mode


SQL> alter system enable restricted session;

System altered.

SQL> drop database;

Database dropped.

限制条件(sql reference 原文)：

drop database

You must have the SYSDBA system privilege to issue this statement. The database

must be mounted in exclusive and restricted mode, and it must be closed.

restricted mode:

RESTRICTED SESSION Clause
The RESTRICTED SESSION clause lets you restrict logon to Oracle.
You can use this clause regardless of whether your instance has the database
dismounted or mounted, open or closed.

Restricting Session Logons: Example You may want to restrict logons if you are
performing application maintenance and you want only application developers
with RESTRICTED SESSION system privilege to log on. To restrict logons, issue the
following statement:
ALTER SYSTEM
ENABLE RESTRICTED SESSION;
You can then terminate any existing sessions using the KILL SESSION clause of the
ALTER SYSTEM statement.
After performing maintenance on your application, issue the following statement to
allow any user with CREATE SESSION system privilege to log on:
ALTER SYSTEM
DISABLE RESTRICTED SESSION;

RESTRICTED SESSION,允许你以约束的方式登录数据库。你可以使用这个子句无论数据库是否挂载或者是否打开。

有四点： 1、拥有SYSDBA 权限。

         2、数据以独享的方式被挂载。

            Oracle 启动存在两种方式:独占和共享

            独占启动的选项是exclusive，表示只允许一个例程使用该数据。

            共享启动的参数是shared,表示允许多个例程并行使用该数据库。    

         3、以RESTRICTED SESSION 登录数据库。

         4、数据库处于关闭状态。

该命令的作用：

When you issue this statement, Oracle Database drops the database and deletes all

control files and datafiles listed in the control file. If the database used a server

parameter file (spfile), it is also deleted.

Archived logs and backups are not removed, but you can use Recovery Manager

(RMAN) to remove them. If the database is on raw disks, this statement does not

delete the actual raw disk special files.

删除控制文件和在控制文件中所列的数据文件，如果数据库正在使用SPfile文件，则一并删除。

备份文件和归档日志文件不会被删除，我们可以之后通过RMAN进行删除。

如果数据库是建立在裸设备上，那么这个命令不会删除指定裸设备上的文件。