SQL>select * from dictionary where instr(comments,''''index'''')>0;
如果我们想知道user_indexes表各字段名称的详细含义，可以用下面这条SQL语句:
SQL>select column_name,comments from dict_columns where table_name=''''USER_INDEXES'''';
依此类推，就可以轻松知道数据字典的详细名称和解释，不用查看ORACLE的其它文档资料了。
下面按类别列出一些ORACLE用户常用数据字典的查询使用方法。
1、用户
查看当前用户的缺省表空间 SQL>select username,default_tablespace from user_users;
查看当前用户的角色 SQL>select * from user_role_privs;
查看当前用户的系统权限和表级权限 SQL>select * from user_sys_privs; SQL>select * from user_tab_privs;
2、表
查看用户下所有的表 SQL>select * from user_tables;
查看名称包含log字符的表 SQL>select object_name,object_id from user_objects where instr(object_name,''''LOG'''')>0;
查看某表的创建时间 SQL>select object_name,created from user_objects where object_name=upper(''''&table_name'''');
查看某表的大小 SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments where segment_name=upper(''''&table_name'''');
查看放在ORACLE的内存区里的表 SQL>select table_name,cache from user_tables where instr(cache,''''Y'''')>0;
3、索引
查看索引个数和类别 SQL>select index_name,index_type,table_name from user_indexes order by table_name;
查看索引被索引的字段 SQL>select * from user_ind_columns where index_name=upper(''''&index_name'''');
查看索引的大小 SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments where segment_name=upper(''''&index_name'''');
4、序列号
查看序列号，last_number是当前值 SQL>select * from user_sequences;
5、视图
查看视图的名称 SQL>select view_name from user_views;
查看创建视图的select语句 SQL>set view_name,text_length from user_views; SQL>set long 2000; 说明：可以根据视图的text_length值设定set long 的大小 SQL>select text from user_views where view_name=upper(''''&view_name'''');
6、同义词
查看同义词的名称 SQL>select * from user_synonyms;
7、约束条件
查看某表的约束条件 SQL>select constraint_name, constraint_type,search_condition, r_constraint_name from user_constraints where table_name = upper(''''&table_name'''');
SQL>select c.constraint_name,c.constraint_type,cc.column_name from user_constraints c,user_cons_columns cc where c.owner = upper(''''&table_owner'''') and c.table_name = upper(''''&table_name'''') and c.owner = cc.owner and c.constraint_name = cc.constraint_name order by cc.position;
8、存储函数和过程
查看函数和过程的状态 SQL>select object_name,status from user_objects where object_type=''''FUNCTION''''; SQL>select object_name,status from user_objects where object_type=''''PROCEDURE'''';
查看函数和过程的源代码 SQL>select text from all_source where owner=user and name=upper(''''&plsql_name'''');
三、查看数据库的SQL 1、查看表空间的名称及大小
select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size from dba_tablespaces t, dba_data_files d where t.tablespace_name = d.tablespace_name group by t.tablespace_name;
2、查看表空间物理文件的名称及大小
select tablespace_name, file_id, file_name, round(bytes/(1024*1024),0) total_space from dba_data_files order by tablespace_name;
3、查看回滚段名称及大小
select segment_name, tablespace_name, r.status, (initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent, max_extents, v.curext CurExtent From dba_rollback_segs r, v$rollstat v Where r.segment_id = v.usn(+) order by segment_name ;
4、查看控制文件
select name from v$controlfile;
5、查看日志文件
select member from v$logfile;
6、查看表空间的使用情况
select sum(bytes)/(1024*1024) as free_space,tablespace_name from dba_free_space group by tablespace_name;
SELECT A.TABLESPACE_NAME,A.BYTES TOTAL,B.BYTES USED, C.BYTES FREE, (B.BYTES*100)/A.BYTES "% USED",(C.BYTES*100)/A.BYTES "% FREE" FROM SYS.SM$TS_AVAIL A,SYS.SM$TS_USED B,SYS.SM$TS_FREE C WHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME AND A.TABLESPACE_NAME=C.TABLESPACE_NAME;
7、查看数据库库对象
select owner, object_type, status, count(*) count# from all_objects group by owner, object_type, status;
8、查看数据库的版本
Select version FROM Product_component_version Where SUBSTR(PRODUCT,1,6)=''''Oracle'''';
9、查看数据库的创建日期和归档方式
Select Created, Log_Mode, Log_Mode From V$Database;jxdco四、ORACLE用户连接的管理
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