一、执行的schema不同，操作的对象也不同

C:\Users\XIFENFEI>sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on 星期日 11月 20 20:39:06 20
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
连接到:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Productio
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
SQL> create user xffa identified by xifenfei;
用户已创建。
SQL> grant connect,resource to xffa;
授权成功。
SQL> create user xffb identified by xifenfei;
用户已创建。
SQL> grant connect,resource to xffb;
授权成功。
SQL> conn xffa/xifenfei
已连接。
xffa>create table tmp(str varchar2(50));
表已创建。
xffa>insert into tmp values
  2  ('my name is xffa');
已创建 1 行。
xffa>commit;
提交完成。
xffa>create or replace procedure definer_proc as
  2      begin
  3        for x in (select sys_context('userenv', 'current_user') current_user,
  4                         sys_context('userenv', 'session_user') session_user,
  5                         sys_context('userenv', 'current_schema') current_sch
ema,
  6                         str
  7                    from tmp) loop
  8        dbms_output.put_line('Current User:   ' || x.current_user);
  9        dbms_output.put_line('Session User:   ' || x.session_user);
 10        dbms_output.put_line('Current Schema: ' || x.current_schema);
 11        dbms_output.put_line('Tables Value:    ' || x.str);
 12      end loop;
 13    end;
 14    /
过程已创建。
xffa>create or replace procedure invoker_proc AUTHID CURRENT_USER as
  2      begin
  3        for x in (select sys_context('userenv', 'current_user') current_user,
  4                         sys_context('userenv', 'session_user') session_user,
  5                         sys_context('userenv', 'current_schema') current_sch
ema,
  6                         str
  7                    from tmp) loop
  8        dbms_output.put_line('Current User:   ' || x.current_user);
  9        dbms_output.put_line('Session User:   ' || x.session_user);
 10        dbms_output.put_line('Current Schema: ' || x.current_schema);
 11        dbms_output.put_line('Tables Value:    ' || x.str);
 12      end loop;
 13    end;
 14    /
过程已创建。
xffa>grant execute on definer_proc to xffb;
授权成功。
xffa>grant execute on invoker_proc to xffb;
授权成功。
xffa>set serveroutput on
xffa>exec definer_proc;
Current User:   XFFA
Session User:   XFFA
Current Schema: XFFA
Tables Value:    my name is xffa
PL/SQL 过程已成功完成。
xffa>exec invoker_proc;
Current User:   XFFA
Session User:   XFFA
Current Schema: XFFA
Tables Value:    my name is xffa
PL/SQL 过程已成功完成。
xffa>conn xffb/xifenfei
已连接。
xffb>exec xffa.definer_proc;
PL/SQL 过程已成功完成。
xffb>set serveroutput on
xffb>exec xffa.definer_proc;
Current User:   XFFA
Session User:   XFFB
Current Schema: XFFA
Tables Value:    my name is xffa
PL/SQL 过程已成功完成。
--除了session是当前用户的，其他都是这个过程所属用户
xffb>exec xffa.invoker_proc;
BEGIN xffa.invoker_proc; END;
*
第 1 行出现错误:
ORA-00942: 表或视图不存在
ORA-06512: 在 "XFFA.INVOKER_PROC", line 3
ORA-06512: 在 line 1
--根据这个提示，很容易知道是tmp表不存在，也就是说明这个没有调用xffa.tmp表
xffb>create table tmp(str varchar2(50));
表已创建。
xffb>insert into tmp values
  2  ('my name is xffb');
已创建 1 行。
xffb>commit;
提交完成。
xffb>exec xffa.invoker_proc;
Current User:   XFFB
Session User:   XFFB
Current Schema: XFFB
Tables Value:    my name is xffb
PL/SQL 过程已成功完成。
--这个可以看出当时调用者的时候，执行的完全是当前用户下面的对象

在定义者(definer)权限下，执行的用户操作的schema为定义者，所操作的对象是定义者在编译时指定的对象。
在调用者(invoker)权限下，执行的用户操作的schema为当前用户，所操作的对象是当前模式下的对象。

二、执行的权限不同

xffb>create or replace procedure createtbl_definer as
  2      begin
  3        execute immediate 'create table xff_definer (id number)';
  4      end;
  5      /
过程已创建。
xffb>create or replace procedure createtbl_invoker AUTHID CURRENT_USER  as
  2      begin
  3        execute immediate 'create table xff_invoker (id number)';
  4      end;
  5      /
xffb>grant execute on createtbl_definer to xffa;
授权成功。
xffb>grant execute on createtbl_invoker to xffa;
授权成功。
xffb>exec createtbl_definer;
BEGIN createtbl_definer; END;
*
第 1 行出现错误:
ORA-01031: 权限不足
ORA-06512: 在 "XFFB.CREATETBL_DEFINER", line 3
ORA-06512: 在 line 1
--提示权限不足，很明显是缺少创建表的权限
xffb>exec createtbl_invoker;
PL/SQL 过程已成功完成。
xffb>desc xff_invoker;
 名称                                      是否为空? 类型
 ----------------------------------------- -------- ----------------------------
 ID                                                 NUMBER
--调用者创建成功
xffb>conn xffa/xifenfei
已连接。
xffa>exec xffb.createtbl_definer;
BEGIN xffb.createtbl_definer; END;
*
第 1 行出现错误:
ORA-01031: 权限不足
ORA-06512: 在 "XFFB.CREATETBL_DEFINER", line 3
ORA-06512: 在 line 1
--定义者同样提示没有权限创建表，通过1中的试验，我们知道
--定义者执行的这个过程定义者的对象，也就是说，是因为xffb无权创建表导致该提示
xffa>exec xffb.createtbl_invoker;
PL/SQL 过程已成功完成。
xffa>desc xff_invoker;
 名称                                      是否为空? 类型
 ----------------------------------------- -------- ----------------------------
 ID                                                 NUMBER
xffa>conn / as sysdba
已连接。
SQL>select owner,table_name from dba_tables where table_name=upper('xff_invoker');
OWNER                          TABLE_NAME
------------------------------ ------------------------------
XFFB                           XFF_INVOKER
XFFA                           XFF_INVOKER
--xffa用户执行成功，并且在自己的schema下面创建了表，证明了1的正确
SQL>GRANT CREATE TABLE TO XFFB;
授权成功。
SQL>conn xffb/xifenfei
已连接。
xffb>exec createtbl_definer;
PL/SQL 过程已成功完成。
xffb>desc xff_definer;
 名称                                      是否为空? 类型
 ----------------------------------------- -------- ----------------------------
 ID                                                 NUMBER
--说明直接授权是的定义者操作成功，但是角色(resource)不能使其操作成功
xffb>conn xffa/xifenfei
已连接。
xffa>exec xffb.createtbl_definer;
BEGIN xffb.createtbl_definer; END;
*
第 1 行出现错误:
ORA-00955: 名称已由现有对象使用
ORA-06512: 在 "XFFB.CREATETBL_DEFINER", line 3
ORA-06512: 在 line 1
--因为定义者执行的是过程创建者的对象，因为XFFB.CREATETBL_DEFINER已经创建成功

在定义者(definer)权限下，当前用户的权限为角色无效情况下所拥有的权限。
在调用者(invoker)权限下，当前用户的权限为当前所拥有的权限(含角色)。

三、执行的效率不同
在定义者(definer)权限下，过程被静态编译静态执行(相对而言)，所执行sql语句在共享区池中是可被共享使用的
在调用者(invoker)权限下，过程静态编译，但动态执行，虽然执行的语句相同，但不同用户执行，其sql语句在共享池中并不能共享。

参考:http://www.itpub.net/thread-935634-1-1.html

DBA_SYS_PRIVS 用户所拥有的系统权限

[oracle@ECP-UC-DB1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.4.0 - Production on Wed Nov 16 13:26:09 2011
Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> create user xff identified by xifenfei;
User created.
SQL> grant connect to xff;
Grant succeeded.
SQL> select * from DBA_SYS_PRIVS where grantee='XFF';
no rows selected
SQL> REVOKE CONNECT FROM XFF;
Revoke succeeded.
SQL> grant create session to xff;
Grant succeeded.
SQL>  select * from DBA_SYS_PRIVS where grantee='XFF';
GRANTEE                        PRIVILEGE                                ADM
------------------------------ ---------------------------------------- ---
XFF                            CREATE SESSION                           NO
SQL> grant select  on chf.t_1 to xff;
Grant succeeded.
SQL>  select * from DBA_SYS_PRIVS where grantee='XFF';
GRANTEE                        PRIVILEGE                                ADM
------------------------------ ---------------------------------------- ---
XFF                            CREATE SESSION                           NO
--说明只能查询系统权限，不能查询角色，不能查询用户权限

DBA_SYS_PRIVS 用户所拥有的角色

SQL> grant resource to xff;
授权成功。
SQL> SELECT * FROM DBA_ROLE_PRIVS WHERE GRANTEE='XFF';
GRANTEE                        GRANTED_ROLE                   ADM DEF
------------------------------ ------------------------------ --- ---
XFF                            RESOURCE                       NO  YES

ROLE_SYS_PRIVS 角色所拥有的系统权限

SQL> SELECT * FROM ROLE_SYS_PRIVS WHERE ROLE='CONNECT';
ROLE                           PRIVILEGE                                ADM
------------------------------ ---------------------------------------- ---
CONNECT                        CREATE SESSION                           NO
SQL> SELECT * FROM ROLE_SYS_PRIVS WHERE ROLE='RESOURCE';
no rows selected
SQL> SELECT * FROM SESSION_ROLES;
ROLE
------------------------------
CONNECT
SQL> CONN / AS SYSDBA
Connected.
SQL> SELECT * FROM ROLE_SYS_PRIVS WHERE ROLE='RESOURCE';
ROLE                           PRIVILEGE                                ADM
------------------------------ ---------------------------------------- ---
RESOURCE                       CREATE TRIGGER                           NO
RESOURCE                       CREATE SEQUENCE                          NO
RESOURCE                       CREATE TYPE                              NO
RESOURCE                       CREATE PROCEDURE                         NO
RESOURCE                       CREATE CLUSTER                           NO
RESOURCE                       CREATE OPERATOR                          NO
RESOURCE                       CREATE INDEXTYPE                         NO
RESOURCE                       CREATE TABLE                             NO
8 rows selected.
--很多时候只能使用sysdba(或者具体特定权限)才能够查询角色有哪些系统权限

ROLE_ROLE_PRIVS: 角色被赋予的角色

SQL> SELECT *FROM ROLE_ROLE_PRIVS WHERE ROLE='DBA';
ROLE                           GRANTED_ROLE                   ADM
------------------------------ ------------------------------ ---
DBA                            OLAP_DBA                       NO
DBA                            SCHEDULER_ADMIN                YES
DBA                            DELETE_CATALOG_ROLE            YES
DBA                            EXECUTE_CATALOG_ROLE           YES
DBA                            WM_ADMIN_ROLE                  NO
DBA                            EXP_FULL_DATABASE              NO
DBA                            SELECT_CATALOG_ROLE            YES
DBA                            JAVA_DEPLOY                    NO
DBA                            GATHER_SYSTEM_STATISTICS       NO
DBA                            JAVA_ADMIN                     NO
DBA                            XDBADMIN                       NO
ROLE                           GRANTED_ROLE                   ADM
------------------------------ ------------------------------ ---
DBA                            IMP_FULL_DATABASE              NO
DBA                            XDBWEBSERVICES                 NO
13 rows selected.

SESSION_PRIVS 当前用户所拥有的全部权限

SQL> conn xff/xifenfei
Connected.
SQL> select * from session_privs;
PRIVILEGE
----------------------------------------
CREATE SESSION
SQL> conn / as sysdba
Connected.
SQL> revoke create session from xff;
Revoke succeeded.
SQL> grant connect to xff;
Grant succeeded.
SQL> conn xff/xifenfei
Connected.
SQL> select * from session_privs;
PRIVILEGE
----------------------------------------
CREATE SESSION
--只能查看系统权限或者角色中包含的系统权限，不能查看用户权限

SESSION_ROLES: 当前用户被激活的角色

SQL> SELECT * from SESSION_ROLES;
no rows selected
SQL> show user;
USER is "SYS"
SQL> conn xff/xifenfei
Connected.
SQL> SELECT *FROM SESSION_ROLES;
ROLE
------------------------------
CONNECT
--sysdba查询无role选项，全部是由系统权限构成

查询某用户的所有系统权限

SQL> SELECT PRIVILEGE, ADMIN_OPTION
  2    FROM DBA_SYS_PRIVS
  3   WHERE GRANTEE = &USERNAME
  4  UNION
  5  --角色转换为权限
  6  SELECT PRIVILEGE, ADMIN_OPTION
  7    FROM ROLE_SYS_PRIVS
  8   WHERE ROLE IN
  9         (SELECT GRANTED_ROLE FROM DBA_ROLE_PRIVS WHERE GRANTEE = &USERNAME)
 10  UNION
 11  --角色的角色转为权限
 12  SELECT PRIVILEGE, ADMIN_OPTION
 13    FROM ROLE_SYS_PRIVS
 14   WHERE ROLE IN (SELECT GRANTED_ROLE
 15                    FROM ROLE_ROLE_PRIVS
 16                   WHERE ROLE IN (SELECT GRANTED_ROLE
 17                                    FROM DBA_ROLE_PRIVS
 18                                   WHERE GRANTEE = &USERNAME));
输入 username 的值:  'XFF'
原值    3:  WHERE GRANTEE = &USERNAME
新值    3:  WHERE GRANTEE = 'XFF'
输入 username 的值:  'XFF'
原值    9:        (SELECT GRANTED_ROLE FROM DBA_ROLE_PRIVS WHERE GRANTEE = &USERNAME)
新值    9:        (SELECT GRANTED_ROLE FROM DBA_ROLE_PRIVS WHERE GRANTEE = 'XFF')
输入 username 的值:  'XFF'
原值   18:                                  WHERE GRANTEE = &USERNAME))
新值   18:                                  WHERE GRANTEE = 'XFF'))
PRIVILEGE                                ADM
---------------------------------------- ---
CREATE CLUSTER                           NO
CREATE INDEXTYPE                         NO
CREATE OPERATOR                          NO
CREATE PROCEDURE                         NO
CREATE SEQUENCE                          NO
CREATE SESSION                           NO
CREATE TABLE                             NO
CREATE TRIGGER                           NO
CREATE TYPE                              NO
UNLIMITED TABLESPACE                     NO
已选择10行。

表相关权限视图

SELECT *FROM TABLE_PRIVILEGES;
SELECT * FROM dba_TAB_PRIVS;
SELECT * FROM ROLE_TAB_PRIVS;

一、sql操作

[oracle@node1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Tue Nov 15 15:00:15 2011
Copyright (c) 1982, 2011, Oracle.  All rights reserved.
Connected to an idle instance.
SQL> startup mount;
ORACLE instance started.
Total System Global Area  417546240 bytes
Fixed Size                  2228944 bytes
Variable Size             285216048 bytes
Database Buffers          121634816 bytes
Redo Buffers                8466432 bytes
Database mounted.
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.
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options

二、alert日志内容

Tue Nov 15 15:00:18 2011
Adjusting the default value of parameter parallel_max_servers
from 320 to 135 due to the value of parameter processes (150)
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Picked latch-free SCN scheme 3
Using LOG_ARCHIVE_DEST_1 parameter default value as USE_DB_RECOVERY_FILE_DEST
Autotune of undo retention is turned on.
IMODE=BR
ILAT =27
LICENSE_MAX_USERS = 0
SYS auditing is disabled
Starting up:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options.
ORACLE_HOME = /opt/oracle/product/11.2.0/db_1
System name:    Linux
Node name:      node1.srtcloud.com
Release:        2.6.18-238.19.1.el5
Version:        #1 SMP Fri Jul 15 07:31:24 EDT 2011
Machine:        x86_64
Using parameter settings in server-side spfile /opt/oracle/product/11.2.0/db_1/dbs/spfilet1.ora
System parameters with non-default values:
  processes                = 150
  memory_target            = 400M
  control_files            = "/opt/oracle/oradata/t1/control01.ctl"
  control_files            = "/opt/oracle/fast_recovery_area/t1/control02.ctl"
  db_block_size            = 8192
  compatible               = "11.2.0.0.0"
  db_recovery_file_dest    = "/opt/oracle/fast_recovery_area"
  db_recovery_file_dest_size= 4122M
  undo_tablespace          = "UNDOTBS1"
  remote_login_passwordfile= "EXCLUSIVE"
  db_domain                = ""
  dispatchers              = "(PROTOCOL=TCP) (SERVICE=t1XDB)"
  local_listener           = "LISTENER_T1"
  audit_file_dest          = "/opt/oracle/admin/t1/adump"
  audit_trail              = "DB"
  db_name                  = "t1"
  open_cursors             = 300
  diagnostic_dest          = "/opt/oracle"
Tue Nov 15 15:00:22 2011
PMON started with pid=2, OS id=26704
Tue Nov 15 15:00:22 2011
PSP0 started with pid=3, OS id=26706
Tue Nov 15 15:00:23 2011
VKTM started with pid=4, OS id=26708 at elevated priority
VKTM running at (1)millisec precision with DBRM quantum (100)ms
Tue Nov 15 15:00:23 2011
GEN0 started with pid=5, OS id=26712
Tue Nov 15 15:00:23 2011
DIAG started with pid=6, OS id=26714
Tue Nov 15 15:00:23 2011
DBRM started with pid=7, OS id=26716
Tue Nov 15 15:00:23 2011
DIA0 started with pid=8, OS id=26718
Tue Nov 15 15:00:23 2011
MMAN started with pid=9, OS id=26720
Tue Nov 15 15:00:23 2011
DBW0 started with pid=10, OS id=26722
Tue Nov 15 15:00:23 2011
LGWR started with pid=11, OS id=26724
Tue Nov 15 15:00:23 2011
CKPT started with pid=12, OS id=26726
Tue Nov 15 15:00:23 2011
SMON started with pid=13, OS id=26728
Tue Nov 15 15:00:23 2011
RECO started with pid=14, OS id=26730
Tue Nov 15 15:00:23 2011
MMON started with pid=15, OS id=26732
Tue Nov 15 15:00:23 2011
MMNL started with pid=16, OS id=26734
starting up 1 dispatcher(s) for network address '(ADDRESS=(PARTIAL=YES)(PROTOCOL=TCP))'...
starting up 1 shared server(s) ...
ORACLE_BASE from environment = /opt/oracle
Tue Nov 15 15:00:23 2011
ALTER DATABASE   MOUNT
Successful mount of redo thread 1, with mount id 2578048199
Database mounted in Exclusive Mode
Lost write protection disabled
Completed: ALTER DATABASE   MOUNT
Tue Nov 15 15:00:33 2011
drop database
ORA-12719 signalled during: drop database...
Tue Nov 15 15:00:47 2011
Stopping background process MMNL
Stopping background process MMON
Starting background process MMON
Tue Nov 15 15:00:49 2011
MMON started with pid=15, OS id=26788
Starting background process MMNL
Tue Nov 15 15:00:49 2011
MMNL started with pid=16, OS id=26790
ALTER SYSTEM enable restricted session;
Tue Nov 15 15:01:06 2011
drop database
Deleted file /opt/oracle/oradata/t1/system01.dbf
Deleted file /opt/oracle/oradata/t1/sysaux01.dbf
Deleted file /opt/oracle/oradata/t1/undotbs01.dbf
Deleted file /opt/oracle/oradata/t1/users01.dbf
Deleted file /opt/oracle/oradata/t1/redo01.log
Deleted file /opt/oracle/oradata/t1/redo02.log
Deleted file /opt/oracle/oradata/t1/redo03.log
Deleted file /opt/oracle/oradata/t1/temp01.dbf
Deleted file /opt/oracle/product/11.2.0/db_1/dbs/snapcf_t1.f
Shutting down archive processes
Archiving is disabled
Create Relation ADR_CONTROL
Create Relation ADR_INVALIDATION
Create Relation INC_METER_IMPT_DEF
Create Relation INC_METER_PK_IMPTS
USER (ospid: 26761): terminating the instance
Instance terminated by USER, pid = 26761
Tue Nov 15 15:01:18 2011
Deleted file /opt/oracle/oradata/t1/control01.ctl
Deleted file /opt/oracle/fast_recovery_area/t1/control02.ctl
Completed: drop database
Shutting down instance (abort)
License high water mark = 1
Tue Nov 15 15:01:32 2011
Instance shutdown complete

三、后续工作
1、清除相关日志trace文件$ORACLE_BASE/diag
2、删除fast_recovery_area文件$ORACLE_BASE/fast_recovery_area
3、删除归档日志(根据配置)
4、删除/etc/oratab中关于该数据库的记录(t1:/opt/oracle/product/11.2.0/db_1:N)

四、补充说明
1、在能够使用dbca删除数据库的情况下，应该选择dbca，这个删除的更加干净
2、dbca删除数据库也需要清理部分文件(如：归档日志)
3、如果对数据库的存储结构比较了解，可以人工关闭数据库后，手工删除相关文件
4、drop database使用于10g及其以上版本