4. COMMENTS VARCHAR2(4000)
SQL> set line 200
SQL> col table_name for a28
SQL> col comments for a120
SQL> show user
USER 为 "SYSTEM"
SQL> select count(*) FROM DICT;
COUNT(*)
----------
2553
SQL> SELECT * FROM DICT WHERE table_name like 'DBA_%' and rownum<11;
TABLE_NAME COMMENTS
------------------------------------------------------------------------------------------------
DBA_2PC_NEIGHBORS information about incoming and outgoing connections for pending transactions
DBA_2PC_PENDING info about distributed transactions awaiting recovery
DBA_ADDM_FDG_BREAKDOWN
DBA_ADDM_FINDINGS
DBA_ADDM_INSTANCES
DBA_ADDM_SYSTEM_DIRECTIVES
DBA_ADDM_TASKS
DBA_ADDM_TASK_DIRECTIVES
DBA_ADVISOR_ACTIONS
DBA_ADVISOR_COMMANDS
已选择 10 行。
SQL>
§1.4.2 积少成多方法记住一些必要的数据字典
Oracle 11g 系统的数据字典多达上千个，要全部记住也没有必要，再说，你
记住数据字典的名称， 还是没有办法记住数据字典内的列的名称及其含义，所以，
我们并不建议要记住很多数据字典，而是将那些重要的、日常要用到的数据字典
记录在自己的秘笈里即可。这里所说的秘笈是你自己习惯的多个文件夹(目录结
构)，比如：
Oracle 10g-常用数据字典与脚本
Oracle 11g-常用数据字典与脚本
6. DBA_tablespaces 表空间有关信息
dba_data_files 数据文件有关信息
dba_free_space 表空间中可用空间的信息
§1.6 附录 2：常用查询脚本(初学者)
下面例子是引导初学者如何查询数据的一些简单脚本，对于中级以上读者可参考网上
的其他文章：
--Oracle 11g 版本：
--查看自己有哪些对象：
Select object_name,object_type,status from user_objects
Order by object_type ;
--
--查询两个对象的依赖关系：
SELECT name, type, referenced_name, referenced_type
FROM user_dependencies
WHERE referenced_name IN ('EMPLOYEES','EMP_VW' );
--
--列出表的依赖关系：
select decode(referenced_type, 'NON-EXISTENT', '.....',
referenced_type) || ' ' || referenced_owner || '.' ||
referenced_name r_name,
' is referenced by: ' || type || ' ' || owner || '.'
||
name name, ' Referenced Link: ' ||
decode(referenced_link_name, null, 'none',
referenced_link_name) r_link
from sys.dba_dependencies
where owner not in ('SYS', 'SYSTEM')
order by 1,2;
--
--直接将系统权限授予用户和角色
select b.privilege what_granted,
b.admin_option, a.username
from sys.dba_users a, sys.dba_sys_privs b
where a.username = b.grantee
order by 1,2;
select privilege what_granted,
admin_option, grantee
from sys.dba_sys_privs
where not exists
7. (select 'x' from sys.dba_users
where username = grantee)
order by 1,2;
--
--查询扩展在 10 次以上的段的信息：
select owner,
segment_name,
segment_type,
tablespace_name,
extents,
max_extents
from sys.dba_segments
where extents > 10
order by tablespace_name;
--
--查询无效对象的信息：
select owner, object_name, object_type,
created, last_ddl_time
from sys.dba_objects
where status = 'INVALID'
order by owner, object_type;
==============全文完================
