本篇文章给大家带来了关于Oracle的相关知识，其中主要整理了数据字典、数据字典视图及动态性能视图的相关问题，数据字典记录数据库最基本的信息，包括数据字典基本表和数据字典视图，下面一起来看一下，希望对大家有帮助。
推荐教程：《Oracle视频教程》
数据字典记录数据库最基本的信息，包括数据字典基本表和数据字典视图；数据字典基本表由 $ORACLE_HOME\RDBMS\ADMIN\sql.bsq创建
数据字典基本表，属于sys用户，存放在system表空间，用户不能手动去修改数据字典基本表；
为了简化对数据字典基本表的使用，oracle提供了数据字典视图，还为数据字典视图创建了公有同义词，方便用户使用，数据字典视图和同义词的创建通过catalog.sql
USER_类型的视图表示当前登录用户拥有的信息；
ALL_类型的视图表示当前登录用户有权限看到的信息；
DBA_类型的视图表示数据库管理员能够看到的信息
如：
对应了2个数据库对象，一个是数据字典视图，一个是同义词，而且是先基于数据字典表创建数据字典视图，然后为视图创建了一个同名的同义词
查询USER_TABLES对应的数据库对象：
select * from dba_objects d where d.OBJECT_NAME='USER_TABLES';
查询USER_TABLES对应的视图：
select * from dba_views d where d.view_name='USER_TABLES';
查询USER_TABLES对应视图的创建语句：
SQL> SET LONG 10000;SQL> select d.text from dba_views d where d.view_name='USER_TABLES';TEXT--------------------------------------------------------------------------------select o.name,
decode(bitand(t.property,2151678048), 0, ts.name,
decode(t.ts#, 0, null, ts.name)),
decode(bitand(t.property, 1024), 0, null, co.name),
decode((bitand(t.property, 512)+bitand(t.flags, 536870912)),
0, null, co.name),
decode(bitand(t.trigflag, 1073741824), 1073741824, 'UNUSABLE', 'VALID'),
decode(bitand(t.property, 32+64), 0, mod(t.pctfree$, 100), 64, 0, null),
decode(bitand(ts.flags, 32), 32, to_number(NULL),
decode(bitand(t.property, 32+64), 0, t.pctused$, 64, 0, null)),
decode(bitand(t.property, 32), 0, t.initrans, null),
decode(bitand(t.property, 32), 0, t.maxtrans, null),
decode(bitand(t.property, 17179869184), 17179869184,
ds.initial_stg * ts.blocksize,
s.iniexts * ts.blocksize),
decode(bitand(t.property, 17179869184), 17179869184,
ds.next_stg * ts.blocksize,
s.extsize * ts.blocksize),
decode(bitand(t.property, 17179869184), 17179869184,
ds.minext_stg, s.minexts),
decode(bitand(t.property, 17179869184), 17179869184,
ds.maxext_stg, s.maxexts),
decode(bitand(ts.flags, 3), 1, to_number(NULL),
decode(bitand(t.property, 17179869184), 17179869184,
ds.pctinc_stg, s.extpct)),
decode(bitand(ts.flags, 32), 32, to_number(NULL),
decode(bitand(o.flags, 2), 2, 1,
decode(bitand(t.property, 17179869184), 17179869184,
ds.frlins_stg, decode(s.lists, 0, 1, s.lists)))),
decode(bitand(ts.flags, 32), 32, to_number(NULL),
decode(bitand(o.flags, 2), 2, 1,
decode(bitand(t.property, 17179869184), 17179869184,
ds.maxins_stg, decode(s.groups, 0, 1, s.groups)))),
decode(bitand(t.property, 32+64), 0,
decode(bitand(t.flags, 32), 0, 'YES', 'NO'), null),
decode(bitand(t.flags,1), 0, 'Y', 1, 'N', '?'),
t.rowcnt,
decode(bitand(t.property, 64), 0, t.blkcnt, null),
decode(bitand(t.property, 64), 0, t.empcnt, null),
decode(bitand(t.property, 64), 0, t.avgspc, null),
t.chncnt, t.avgrln, t.avgspc_flb,
decode(bitand(t.property, 64), 0, t.flbcnt, null),
lpad(decode(t.degree, 32767, 'DEFAULT', nvl(t.degree,1)),10),
lpad(decode(t.instances, 32767, 'DEFAULT', nvl(t.instances,1)),10),
lpad(decode(bitand(t.flags, 8), 8, 'Y', 'N'),5),
decode(bitand(t.flags, 6), 0, 'ENABLED', 'DISABLED'),
t.samplesize, t.analyzetime,
decode(bitand(t.property, 32), 32, 'YES', 'NO'),
decode(bitand(t.property, 64), 64, 'IOT',
decode(bitand(t.property, 512), 512, 'IOT_OVERFLOW',
decode(bitand(t.flags, 536870912), 536870912, 'IOT_MAPPING', null))),
decode(bitand(o.flags, 2), 0, 'N', 2, 'Y', 'N'),
decode(bitand(o.flags, 16), 0, 'N', 16, 'Y', 'N'),
decode(bitand(t.property, 8192), 8192, 'YES',
decode(bitand(t.property, 1), 0, 'NO', 'YES')),
decode(bitand(o.flags, 2), 2, 'DEFAULT',
decode(bitand(decode(bitand(t.property, 17179869184), 17179869184,
ds.bfp_stg, s.cachehint), 3),
1, 'KEEP', 2, 'RECYCLE', 'DEFAULT')),
decode(bitand(o.flags, 2), 2, 'DEFAULT',
decode(bitand(decode(bitand(t.property, 17179869184), 17179869184,
ds.bfp_stg, s.cachehint), 12)/4,
1, 'KEEP', 2, 'NONE', 'DEFAULT')),
decode(bitand(o.flags, 2), 2, 'DEFAULT',
decode(bitand(decode(bitand(t.property, 17179869184), 17179869184,
ds.bfp_stg, s.cachehint), 48)/16,
1, 'KEEP', 2, 'NONE', 'DEFAULT')),
decode(bitand(t.flags, 131072), 131072, 'ENABLED', 'DISABLED'),
decode(bitand(t.flags, 512), 0, 'NO', 'YES'),
decode(bitand(t.flags, 256), 0, 'NO', 'YES'),
decode(bitand(o.flags, 2), 0, NULL,
decode(bitand(t.property, 8388608), 8388608,
'SYS$SESSION', 'SYS$TRANSACTION')),
decode(bitand(t.flags, 1024), 1024, 'ENABLED', 'DISABLED'),
decode(bitand(o.flags, 2), 2, 'NO',
decode(bitand(t.property, 2147483648), 2147483648, 'NO',
decode(ksppcv.ksppstvl, 'TRUE', 'YES', 'NO'))),
decode(bitand(t.property, 1024), 0, null, cu.name),
decode(bitand(t.flags, 8388608), 8388608, 'ENABLED', 'DISABLED'),
case when (bitand(t.property, 32) = 32) then
null
when (bitand(t.property, 17179869184) = 17179869184) then
decode(bitand(ds.flags_stg, 4), 4, 'ENABLED', 'DISABLED')
else
decode(bitand(s.spare1, 2048), 2048, 'ENABLED', 'DISABLED')
end,
case when (bitand(t.property, 32) = 32) then
null
when (bitand(t.property, 17179869184) = 17179869184) then
decode(bitand(ds.flags_stg, 4), 4,
case when bitand(ds.cmpflag_stg, 3) = 1 then 'BASIC'
when bitand(ds.cmpflag_stg, 3) = 2 then 'OLTP'
else decode(ds.cmplvl_stg, 1, 'QUERY LOW',
2, 'QUERY HIGH',
3, 'ARCHIVE LOW',
'ARCHIVE HIGH') end,
null)
else
decode(bitand(s.spare1, 2048), 0, null,
case when bitand(s.spare1, 16777216) = 16777216 -- 0x1000000
then 'OLTP'
when bitand(s.spare1, 100663296) = 33554432 -- 0x2000000
then 'QUERY LOW'
when bitand(s.spare1, 100663296) = 67108864 -- 0x4000000
then 'QUERY HIGH'
when bitand(s.spare1, 100663296) = 100663296 -- 0x2000000+0x4000000
then 'ARCHIVE LOW'
when bitand(s.spare1, 134217728) = 134217728 -- 0x8000000
then 'ARCHIVE HIGH'
else 'BASIC' end)
end,
decode(bitand(o.flags, 128), 128, 'YES', 'NO'),
decode(bitand(t.trigflag, 2097152), 2097152, 'YES', 'NO'),
decode(bitand(t.property, 17179869184), 17179869184, 'NO',
decode(bitand(t.property, 32), 32, 'N/A', 'YES')),
decode(bitand(t.property,16492674416640),2199023255552,'FORCE',
4398046511104,'MANUAL','DEFAULT')from sys.ts$ ts, sys.seg$ s, sys.obj$ co, sys.tab$ t, sys.obj$ o,
sys.deferred_stg$ ds, sys.obj$ cx, sys.user$ cu, x$ksppcv ksppcv,
x$ksppi ksppiwhere o.owner# = userenv('SCHEMAID')
and o.obj# = t.obj#
and bitand(t.property, 1) = 0
and bitand(o.flags, 128) = 0
and t.bobj# = co.obj# (+)
and t.ts# = ts.ts#
and t.file# = s.file# (+)
and t.block# = s.block# (+)
and t.ts# = s.ts# (+)
and t.obj# = ds.obj# (+)
and t.dataobj# = cx.obj# (+)
and cx.owner# = cu.user# (+)
and ksppi.indx = ksppcv.indx and ksppi.ksppinm = '_dml_monitoring_enabled'查询同义词：
select * from dba_synonyms d where d.synonym_name='USER_TABLES'
查询当前登录用户拥有的表
存储数据库中每时每刻都在变化的信息，主要是数据库的活动状态信息。把存储在内存里的信息，和存储在控制文件里的信息，以视图的形式展现出来；
初始化参数文件中所有项的值
当前进程的信息
有关会话的信息
基于当前操作会话进行的系统统计
从控制文件中提取有关重做日志组的信息
有关实例重做日志组文件名及其位置的信息
当前进程已获得和正在请求的锁信息
数据库事务信息
记录所有动态性能视图的定义信息
推荐教程：《Oracle视频教程》
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