oracle物化视图

Sun, 29 Apr 2012 00:38:00 GMT

一、oracle物化视图基本概念

物化视图首先需要创建物化视图日�?

oracle依据用户创徏的物化视图日志来创徏物化视图日志表，

物化视图日志表的名称为mlog$_后面跟基表的名称�Q?/div>

如果表名的长度超�q?0位，则只取前20位，当截短后出现名称重复�Ӟ��oracle会自动在物化视图日志名称后面加上数字作�ؓ序号�?/div>

创徏物化视图日志在徏立时有多�U�选项�Q�可以指定�ؓrowid、primary key和object id几种�c�d��Q�同时还可以指定sequence或明��指定列名�?/div>

上面�q�些情况产生的物化视图日志的�l�构都不相同�?/div>

��M��物化视图都会包括的列�Q?/div>

snaptime$$�Q�用于表�C�刷新时间�?/div>

dmltype$$�Q�用于表�C�dml操作�c�d��Q�i表示insert�Q�d表示delete�Q�u表示update�?/div>

old_new$$�Q�用于表�C��个值是新��D��是旧倹{��n�Q�ew�Q�表�C�新��|��o�Q�ld�Q�表�C�旧��|��u表示update操作�?/div>

change_vector$$表示修改矢量�Q�用来表�C��修改的是哪个或哪几个字段�?/div>

如果with后面跟了primary key�Q�则物化视图日志中会包含主键列�?/div>

如果with后面跟了rowid�Q�则物化视图日志中会包含�Q?m_row$$�Q�用来存储发生变化的记录的rowid�?/div>

如果with后面跟了object id�Q�则物化视图日志中会包含�Q�sys_nc_oid$�Q�用来记录每个变化对象的对象id�?/div>

如果with后面跟了sequence�Q�则物化视图日子中会包含�Q�sequence$$�Q�给每个操作一个sequence��P��从而保证刷新时按照��序�q�行��h��?/div>

如果with后面跟了一个或多个column名称�Q�则物化视图日志中会包含�q�些列�?/div>

二、oracle物化视图日志

1.primary key

drop table test_id; --删除�?/div>

create table test_id(id number,name varchar2(30),mark number); --创徏�?/div>

alter table test_id add constraint pk_test_id primary key (id); --增加主键

drop materialized view log on test_id;--删除物化视图日志

create materialized view log on test_id tablespace ttts with primary key; --依据主键创徏物化视图日志

--�pȝ��针对日志��

sql> desc mlog$_test_id;

name type nullable default comments

--------------- ----------- -------- ------- --------

id number y 用主键记录发生dml操作的行

snaptime$$ date y snaptime$$列记录了��h��操作的时间�?

dmltype$$ varchar2(1) y dmltype$$的记录值i、u和d�Q�表�C�操作是insert、update�q�是delete�?

old_new$$ varchar2(1) y old_new$$表示物化视图日志中保存的信息是dml操作之前的��|��旧��|��q�是dml操作之后的��|��新��|��。除了o和n�q�两�U�类型外�Q�对于update操作�Q�还可能表示为u�?

change_vector$$ raw(255) y change_vector$$记录dml操作发生在那个或那几个字�D�上

--当创建物化视图日志��用primary key�Ӟ��oracle创徏临时�?RUPD$_基础�?/div>

sql> desc rupd$_test_id;

name type nullable default comments

--------------- ----------- -------- ------- --------

id number y

dmltype$$ varchar2(1) y

snapid integer y

change_vector$$ raw(255) y

2.rowid

drop table test_rowid; --删除�?/div>

create table test_rowid(id number,name varchar2(30),mark number); --创徏�?/div>

drop materrialized view log on test_rowid;

--create materialized view log on test_rowid with rowid, sequence (id, name) including new values ;

create materialized view log on test_rowid with rowid;--依据rowid创徏物化视图日志

sql> desc mlog$_test_rowid;

name type nullable default comments

--------------- ------------- -------- ------- --------

m_row$$ varchar2(255) y

snaptime$$ date y

dmltype$$ varchar2(1) y

old_new$$ varchar2(1) y

change_vector$$ raw(255) y

3.object id

create type test_object as object (id number, name varchar2(30), num number);--创徏�c�d��

create table test_objid of test_object; --创徏�?/div>

create materialized view log on test_objid with object id;--依据object id创徏物化视图日志

sql> desc mlog$_test_objid;

name type nullable default comments

--------------- ----------- -------- ------- --------

sys_nc_oid$ raw(16) y

snaptime$$ date y

dmltype$$ varchar2(1) y

old_new$$ varchar2(1) y

change_vector$$ raw(255) y

4.sequence+rowid+(属性列)

drop table test_sq; --删除�?/div>

create table test_sq(id number,name varchar2(30),mark number); --创徏�?/div>

drop materialized view log on test_sq;--删除物化视图日志

create materialized view log on test_sq tablespace ttts with sequence; --依据sequence创徏物化视图日志

--ora-12014: �?'test_sq' 不包含主键约束条�?/div>

create materialized view log on test_sq with sequence (id, name,num) including new values;--包含基础表的所有列

--ora-12014: �?'test_sq' 不包含主键约束条�?/div>

alter table test_sq add constraint uk_test_sq unique (id,name); --增加uk

create materialized view log on test_sq with sequence (id,name) including new values;

--ora-12014: �?'test_sq' 不包含主键约束条�?/div>

即主键、rowid或object id用来唯一表示物化视图日志中的记录�Q�sequence不能唯一标识记录�Q�故不能单独用来建日志�?/div>

create materialized view log on test_sq with rowid,sequence (id, name) including new values ;

sql> desc mlog$_test_sq;

name type nullable default comments

--------------- ------------- -------- ------- --------

id number y 建立物化视图时指明的列会在物化视图日志中�q�行记录�?

name varchar2(30) y

m_row$$ varchar2(255) y

sequence$$ number y sequence会根据操作发生的��序对物化视图日志中的记录编受��?

snaptime$$ date y

dmltype$$ varchar2(1) y

old_new$$ varchar2(1) y

change_vector$$ raw(255) y

三、oracle物化视图日志�?/div>

基础表：test_id�Q�test_rowid�Q�test_objid�Q�test_sq

日志表：mlog$_test_id�Q�mlog$_test_rowid�Q�mlog$_test_objid�Q�mlog$_test_sq

1.新增

insert into test_id values (1, 'a', 5);

insert into test_rowid values (1, 'a', 5);

insert into test_objid values (1, 'a', 5);

insert into test_sq values (1, 'a', 5);

commit;

2.修改

update test_id set name = 'c' where id = 1;

update test_rowid set name = 'c' where id = 1;

update test_objid set name = 'c' where id = 1;

update test_sq set name = 'c' where id = 1;

commit;

3.删除

delete test_id ;

delete test_rowid;

delete test_objid;

delete test_sq ;

commit;

在每一步commit后查看日志表记录�?/div>

四、oracle物化视图日志表字�D�取��D��?/div>

1.snaptime$$

当基本表发生dml操作�Ӟ��会记录到物化视图日志中，�q�时指定的时�?000�q?�?�?�?�?�U�（物化视图未被��h��Q��?/div>

如果物化视图日志供多个物化视图��用，则一个物化视囑ֈ�新后会将它刷新的记录的时间更��Cؓ它刷新的旉��?/div>

只有建立快速刷新的物化视图才能使用物化视图日志�Q�如果只建立一个物化视图，则物化视囑ֈ�新完会将物化视图日志清除�?/div>

2.dmltype$$

操作�c�d��比较��单：只包括i(insert)、d(delete)和u(update)三种�?/div>

3.old_new$$

新旧��g��包括三种�Q�o表示旧��|��一般对应的操作时delete�Q�、n表示新��|��一般对应的操作是insert�Q�，�q�有一�U�u�Q�对应update操作�Q��?nbsp;

需要注意，对于��Z��主键的物化视图日志，如果更新了主键，则update操作转化��Z��条delete操作�Q�一条insert操作。最后是delete操作�?nbsp;

唯一的区别是每条update操作都对应物化视图日志中的两条记录�?/div>

一条对应update操作的原记录dmltype$$和old_new$$都�ؓu�Q�一条对应update操作后的新记录，dmltype$$为u�Q�old_new$$为n�?/div>

当徏立物化视图日志时指出了including new values语句�Ӟ��׃��出现�q�种情况�?nbsp;

4.change_vector$$

最后简单讨��Z��下change_vector$$列�?/div>

insert和delete操作都是记录集的�Q�即insert和delete会媄响整条记录�?/div>

而update操作是字�D�集的，update操作可能会更新整条记录的所有字�D�，也可能只更新个别字段�?/div>

无论从性能上考虑�q�是从数据的一致性上考虑�Q�物化视囑ֈ�新时都应该是��Z��字段集�?/div>

oracle��是通过change_vector$$列来记录每条记录发生变化的字�D�包括哪些�?/div>

��Z��主键、rowid和object id的物化视图日志在change_vector$$上略有不同，但是��M��设计的思�\是一致的�?/div>

change_vector$$列是raw�c�d��Q�其实oracle采用的方式就是用每个bit位去映射一个列�?/div>

比如�Q�第一列被更新讄��?2�Q�即00000010�?/div>

�W�二列设�|��ؓ04�Q�即00000100�Q?/div>

�W�三列设�|��ؓ08�Q�即00001000�?/div>

当第一列和�W�二列同时被更新�Q�则讄��?6�Q?0000110�?/div>

如果三列都被更新�Q�设�|��ؓ0e�Q?0001110�?/div>

依此�c�L��Q�第4列被更新时�ؓ0x10�Q�第5�?x20�Q�第6�?x40�Q�第7�?x80�Q�第8�?x100�?/div>

当第1000列被更新�Ӟ��change_vector$$的长度�ؓ1000/4+2�?52�?/div>

除了可以表示update的字�D�，�q�可以表�C�insert和delete。delete操作change_vector$$列�ؓ�?�Q�具体个数由��的列数决定�?/div>

insert操作的最低位为fe�Q�如果基表列数较多，而存在高位的话，所有的高位都�ؓff�?/div>

如果insert操作是前面讨��的由update操作更新了主键造成的，则这个insert操作对应的change_vector$$列�ؓ全ff�?/div>

可以看到�Q�正如上面分析的�Q�insert为fe�Q�delete�?0�Q�对�W�一列的更新�?2�Q�第二列�?4�Q�第二列和第三列都更��Cؓ0c。需要注意，正常情况下，�W�一列会�?2开始�?/div>

但是如果对mlog$表执行了truncate操作�Q�或者重��Z��物化视图日志�Q�则可能造成�W�一列开始位�|�发生偏�U�R�?/div>

�q�个�l�果和rowid�c�d��基本一��_��不同的是�Q�如果更��C��主键�Q�会��update操作在物化视图日志中记录��Z��条delete和一条insert�Q�不�q�这时insert对应的change_vector$$的值是ff�?/div>

�q�个�l�果也和rowid�c�d��基本一��_��需要注意的是，�׃��对象表包含两个隐含列�Q�因此id不再是第一个字�D�，而是�W�三个，因此对应的值是08�?/div>

最后看一个包含列数较多的例子�Q�唯一需要注意的是，低位在左�Q�高位在叟�?/div>

五、oracle物化视图

1.物化视图mv_test_id

create materialized view mv_test_id refresh fast on commit as

select * from test_id; --commit时物化视图被��h��

2.物化视图mv_test_rowid

create materialized view mv_test_rowid refresh fast as

select name, count(*) from test_rowid group by name;

--ORA-32401: "TT"."TEST_ROWID" 上的实体化视图日志没有新�?/div>

alter materialized view log on test_rowid add including new values;

create materialized view mv_test_rowid refresh fast as

select name, count(*) from test_rowid group by name;

--ORA-12033: 不能使用 "TT"."TEST_ROWID" 上实体化视图日志中的�q��o器列

alter materialized view log on test_rowid add (name);

create materialized view mv_test_rowid refresh fast as

select name, count(*) from test_rowid group by name;

3.物化视图mv_test_objid

create materialized view mv_test_objid refresh fast as

select * from test_objid;

--ORA-12014: �?'TEST_OBJID' 不包含主键约束条�?/div>

alter table test_objid add constraint pk_test_objid primary key (id); --增加主键

create materialized view mv_test_objid refresh fast as

select * from test_objid;

--ORA-23415: "TT"."TEST_OBJID" 的实体化视图日志不记录主�?

alter materialized view log on test_objid add (id);

alter materialized view log on test_objid add primary key (id);

drop materialized view log on test_objid;

create materialized view log on test_objid tablespace ttts with primary key including new values;

create materialized view mv_test_objid refresh fast as

select * from test_objid;

4.物化视图mv_test_sq

create materialized view mv_test_sq refresh fast as

select name, count(*) from test_sq group by name; --需要用exec dbms_mview.refresh('mv_test_sq')来刷�?/div>

5.物化视图��h��

exec dbms_mview.refresh('mv_test_rowid');

exec dbms_mview.refresh('mv_test_objid');

exec dbms_mview.refresh('mv_test_sq');

物化视图��h��后日志表记录被清�I��?/div>

refresh fast as 调用exec dbms_mview.refresh('mv_基本�?)时物化视囑ֈ��?/div>

refresh fast on commit as 在commit时物化视囑ֈ��?/div>

refresh fast on demand 定时物化视图��h��

create materialized view mv_test_sq2 refresh fast on demand

with rowid start with to_date('22-04-2011 16:30:01', 'dd-mm-yyyy hh24:mi:ss') next /*1:hrs*/ sysdate + 1/(24*60)

as select id,count(*) from test_sq group by id;

六、错误提�C�：

--ORA-32401: "TT"."TEST_ROWID" 上的实体化视图日志没有新�?/div>

alter materialized view log on test_rowid add including new values;

--ORA-12033: 不能使用 "TT"."TEST_ROWID" 上实体化视图日志中的�q��o器列

alter materialized view log on test_rowid add (name);

--ORA-12014: �?'TEST_OBJID' 不包含主键约束条�?/div>

alter table test_objid add constraint pk_test_objid primary key (id); --增加主键

--ORA-23415: "TT"."TEST_OBJID" 的实体化视图日志不记录主�?/div>

drop materialized view log on test_objid;

create materialized view log on test_objid tablespace ttts with primary key including new values;

七、相兌��法：

create {materialized view | snapshot} log on [tablespace ] [storage (…)] [pctfree <10>] [pctused <40>] [initrans <1>] [maxtrans ] [logging | nologging] [cache | nocache] [noparallel | parallel []] [partition…] [lob…] [using index…] [with [primary key] [, rowid] [( [, …])] ] [{including | excluding} new values];

alter {materialized view | snapshot} log on [add [primary key] [, rowid] [( [, …])] ] […];

drop {materialized view | snapshot} log on ;

create {materialized view | snapshot} [tablespace ] [storage (…)] [pctfree <10>] [pctused <40>] [initrans <1>] [maxtrans ] [logging | nologging] [cache | nocache] [noparallel | parallel []] [cluster ( [, …])] [lob…] [partition…] [build {immediate | deferred}] [on prebuilt table [{with | without} reduced precision]] [using index…] [ refresh [fast | complete | force] [on commit | on demand] [start with ‘’] [next ‘’] [with {primary key | rowid}] [using [default] [master | local] rollback segment []] ] | never refresh ] [for update] [{enable | disable} query rewrite] as ;

alter {materialized view | snapshot} … [compile];

drop {materialized view | snapshot} ;

八、�D�?/div>

connect pubr/bit@datasource ;

drop materialized view log on pubr.allactive; --删除物化视图日志

create materialized view log

on pubr.allactive tablespace logts with primary key; --创徏物化视图日志

connect ttowb/bit;

drop materialized view allactive_tt; --删除物化视图

create materialized view allactive_tt

refresh fast

as select ID,CATEGORY,FLOWID,MASTATUS,BASTATUS,APPLYDATETIME,CREATEDATETIME,COMMITDATETIME,BITSPNO,ARCHIVETIME,

DESCRIPTION,OPERTYPE,ISVALID,INVALIDREASON,INVALIDDATETIME,INVALIDPNO,ACTIVETABLENAME,PARENTID,STANID,REALTYPEID,

CORRECTID,to_date('1900-01-01') allactive_rtime from pubr.allactive@pubrowb; --创徏物化视图

�?ji��)、参�?/div>

http://tech.ddvip.com/2008-09/122180687967473.html Oracle物化视图�Q�创建最��单物化视�?/div>

http://yangtingkun.itpub.net/post/468/20584 Oracle如何�Ҏ(gu��)��物化视图日志快速刷新物化视�?/div>

http://blog.itpub.net/post/468/20498 物化视图日志�l�构

执着那䆾�?/a> 2012-04-29 08:38 发表评论

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oracle物化视图