一、用户表数据查询

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 tabs

        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 ind

        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 seq

        查看序列号，last_number是当前值 
        SQL>select * from user_sequences; 或 select * from seq;

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\’); 

9、获取创建表语句

　　　设置输出长度

　　　SQL> SET LONG 9999;

　　　SQL> SELECT DBMS_METADATA.GET_DDL(\’TABLE\’,\’tablename\’) FROM DUAL;

二、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;