oracle的基本信息查询

oracle查看当前数据库实例名
select name from V$DATABASE;
或者
select SYS_CONTEXT('USERENV','INSTANCE_NAME') from dual;
查看Oracle当前用户下的信息（用户，表视图，索引，表空间，同义词，存储过程函数，约束条件）
0、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; --查看用户下所有的表
SQL>select * from user_tables;
1、用户
SQL>select username,default_tablespace from user_users; --看当前用户的缺省表空间
SQL>select * from user_role_privs; --查看当前用户的角色
SQL>select * from user_sys_privs; --查看当前用户的系统权限和表级权限 SQL>select * from user_tab_privs;
SQL>select * from session_privs; --显示当前会话所具有的权限
SQL>select * from dba_sys_privs where grantee='YANG'; --显示指定用户所具有的系统权限
2、表
SQL>select * from user_tables; --查看用户下所有的表
SQL>select object_name,object_id from user_objects where instr(object_name,'LOG')>0; --看名称包含log字符的表
SQL>select object_name,created from user_objects where object_name=upper('&table_name'); --查看某表的创建时间
SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments where segment_name=upper('&table_name'); --查看某表的大小
SQL>select table_name,cache from user_tables where instr(cache,'Y')>0; --查看放在ORACLE的内存区里的表
3、索引
SQL>select index_name,index_type,table_name from user_indexes order by table_name; --查看索引个数和类别
SQL>select * from user_ind_columns where index_name=upper('&index_name'); --查看索引被索引的字段
SQL>select sum(bytes)/(1024*1024) as "size(M)" from user_segments where segment_name=upper('&index_name'); --查看索引的大小
4、序列号
SQL>select * from user_sequences; --查看序列号，last_number是当前值
5、视图
SQL>select view_name from user_views; --查看视图的名称
SQL>select view_name,text_length from user_views; --查看创建视图的select语句
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
SQL>select * from user_synonyms; --查看同义词的名称
7、约束条件
SQL>select constraint_name, constraint_type,search_condition, r_constraint_name from user_constraints where table_name = upper('&table_name'); --查看某表的约束条件
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
SQL>select object_name,status from user_objects where object_type='FUNCTION'; --查看函数和过程的状态
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');