我们都知道一般我们都可以通过查询v$parameter视图或者show parameter的命令来获得Oracle数据库参数的值，而且x$ksppcv和x$ksppi这两个内部视图是我们v$parameter视图的源表：
SQL> select view_definition from v$fixed_view_definition where view_name='V$PARAMETER';
VIEW_DEFINITION
--------------------------------------------------------------------------------
select NUM , NAME , TYPE , VALUE , ISDEFAULT , ISSES_MODIFIABLE , ISSYS_MODIFIA
BLE , ISMODIFIED , ISADJUSTED , DESCRIPTION, UPDATE_COMMENT from GV$PARAMETER wh
ere inst_id = USERENV('Instance')
SQL> select view_definition from v$fixed_view_definition where view_name='GV$PARAMETER';
VIEW_DEFINITION
--------------------------------------------------------------------------------
select x.inst_id,x.indx+1,ksppinm,ksppity,ksppstvl,ksppstdf, decode(bitand(kspp
iflg/256,1),1,'TRUE','FALSE'), decode(bitand(ksppiflg/65536,3),1,'IMMEDIATE',2,
'DEFERRED', 3,'IMMEDIATE','FALSE'), decode(bit
and(ksppstvf,7),1,'MODIFIED',4,'SYSTEM_MOD','FALSE'), decode(bitand(ksppstvf,2)
,2,'TRUE','FALSE'), ksppdesc, ksppstcmnt from x$ksppi x, x$ksppcv y where (x.i
ndx = y.indx) and ((translate(ksppinm,'_','#') not like '#%') or (ksppstdf = 'F
ALSE'))
有些_开头的隐含参数被隐去了，我们可以通过如下脚本来查询我们的隐含参数
set linesize 100
set pagesize 9999
column name format a30
column value format a25
select
x.ksppinm name,
y.ksppstvl value,
y.ksppstdf isdefault,
decode(bitand(y.ksppstvf,7),1,'MODIFIED',4,'SYSTEM_MOD','FALSE') ismod,
decode(bitand(y.ksppstvf,2),2,'TRUE','FALSE') isadj
from
sys.x$ksppi x,
sys.x$ksppcv y
where
x.inst_id = userenv('Instance') and
y.inst_id = userenv('Instance') and
x.indx = y.indx and
x.ksppinm like '%_&par%'
order by
translate(x.ksppinm, ' _', ' ')；
