How to generate materialized views?

Hi,
I have some entities in my ERD that have to be generated as materialized views. The rest will be normally tables. Notice that there are relations between Materialized Views and tables.
Can anyone advise me?

Well, it's considered "bad form" to define de-normalized content as Entities.
So ... there isn't any way to directly transform Entities into MVs. However, once you transform some Entities into Tables, you'll find that the Design Editor wizards do a nice job of allowing to define Materialized Views based on those now-existant Table definitions.
What I would do is add some Notes to the Entities that are going to need to be implemented as Tables and as MVs. Since the Notes carry through. And then make sure to read through the Table Notes when you're refining your Tables and build the MVs at that time.

Similar Messages

How to refresh materialized view by trigger

hi,
im having a problem in refreshing materialized view through a trigger.
CREATE OR REPLACE TRIGGER L_TRG_MARC_TEST
BEFORE DELETE OR INSERT OR UPDATE ON MARC_BOOK_B_ENG
BEGIN
DBMS_MVIEW.REFRESH('TITLE_ENG_MV','C','',TRUE,FALSE,0,0,0,TRUE);
END;
Trigger created.
SQL> DELETE FROM MARC_BOOK_B_ENG;
DELETE FROM MARC_BOOK_B_ENG
ERROR at line 1:
ORA-04092: cannot COMMIT in a trigger
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 849
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 832
ORA-06512: at "LIBQAL1.L_TRG_MARC_TEST", line 2
ORA-04088: error during execution of trigger 'LIBQAL1.L_TRG_MARC_TEST'
plz tell me how to refresh materialized view thru trigger,,and what is wrong in above mentioned situation.
Regards

DBMS_MVIEW.REFRESH implicitly commits. COMMIT is not permitted in triggers, as you can see, unless you use AUTONOMOUS_TRANSACTION.
Try
CREATE OR REPLACE TRIGGER L_TRG_MARC_TEST
BEFORE DELETE OR INSERT OR UPDATE ON MARC_BOOK_B_ENG
DECLARE
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
DBMS_MVIEW.REFRESH('TITLE_ENG_MV','C','',TRUE,FALSE,0,0,0,TRUE);
END;

How to find Materialized views in OBIEE

Hi gurus,
how to find materialized views which are used in OBIEE?
Do We see them in view log session after running a report?
I have a requirement to find MV'S.Do we use MV'S in OBIEE?What is the use of MV?
Kindly answer me.
Thanks,
siva

Refer
http://gerardnico.com/wiki/database/oracle/materialized_view

How to get Materialized View to ignore unused columns in source table

When updating a column in a source table, records are generated in the corresponding materialized view log table. This happens even if the column being updated is not used in any MV that references the source table. That could be OK, so long as those updates are ignored. However they are not ignored, so when the MV is fast refreshed, I find it can take over a minute, even though no changes are required or made. Is there some way of configuring the materialized view log such that the materialized view refresh ignores these updates ?
So for examle if I have table TEST:
CREATE table test (
d_id NUMBER(10) PRIMARY KEY,
d_name VARCHAR2(100),
d_desc VARCHAR2(256)
This has an MV log MLOG$_TEST:
CREATE MATERIALIZED VIEW LOG ON TEST with rowid, sequence, primary key;
CREATE MATERIALIZED VIEW test_mv
refresh fast on demand
as
select d_id, d_name
from test;
INSERT 200,000 records
exec dbms_mview.refresh('TEST_MV','f');
update test set d_desc = upper(d_desc) ;
exec dbms_mview.refresh('TEST_MV','f'); -- This takes 37 seconds, yet no changes are required.
Oracle 10g/11g

I would love to hear a positive answer to this question - I have the exact same issue :-)
In the "old" days (version 8 I think it was) populating the materialized view logs was done by Oracle auto-creating triggers on the base table. A "trick" could then make that trigger become "FOR UPDATE OF <used_column_list>". Now-a-days it has been internalized so such "triggers" are not visible and modifiable by us mere mortals.
I have not found a way to explicitly tell Oracle "only populate MV log for updates of these columns." I think the underlying reason is that the MV log potentially could be used for several different materialized views at possibly several different target databases. So to be safe that the MV log can be used for any MV created in the future - Oracle always populates MV log at any update (I think.)
One way around the problem is to migrate to STREAMS replication rather than materialized views - but it seems to me like swatting a fly with a bowling ball...
One thing to be aware of: Once the MV log has been "bloated" with a lot of unneccessary logging, you may perhaps see that all your FAST REFRESHes afterwards becomes slow - even after the one that checked all the 200000 unneccessary updates. We have seen that it can happen that Oracle decides on full table scanning the MV log when it does a fast refresh - which usually makes sense. But after a "bloat" has happened, the high water mark of the MV log is now unnaturally high, which can make the full table scan slow by scanning a lot of empty blocks.
We have a nightly job that checks each MV log if it is empty. If it is empty, it locks the MV log and locks the base table, checks for emptiness again, and truncates the MV log if it is still empty, before finally unlocking the tables. That way if an update during the day has happened to bloat the MV log, all the empty space in the MV log will be reclaimed at night.
But I hope someone can answer both you and me with a better solution ;-)

How to use materialized view in stored procedure

in my stored procedure I use couple of queries (see the script below). I want to create materialized views to replace these queries. Is it possible to achieve and how to achieve it in my case? thanks in advance
set serveroutput on
DECLARE
v_cur_tid NUMBER(5):=0;
v_cur_cs_attendance NUMBER(5):=0;
v_cur_c_tot_enrolments NUMBER(5):=0;
v_most_enrolments NUMBER(5):=0;
v_least_enrolments NUMBER(5):=0;
v_most_pop_cid NUMBER(5):=0;
v_least_pop_cid NUMBER(5):=0;
CURSOR class_cursor IS
select
id,
name,
max_attendees
from
class
where
id in (select distinct(event_id) from trainer_schedule where event_type='c' and is_active='y')
order by id;
BEGIN
DBMS_OUTPUT.PUT_LINE('==================================================================================================================================');
--print the report header
DBMS_OUTPUT.PUT_LINE('Summary Report No.3: Training Class Active Schedules Summary Report');
FOR r_class IN class_cursor LOOP
--print the header or subsection
select sum(enrolments) into v_cur_c_tot_enrolments from class_schedule where class_id = r_class.id;
IF v_most_enrolments < v_cur_c_tot_enrolments OR v_most_enrolments = 0
THEN v_most_enrolments := v_cur_c_tot_enrolments; v_most_pop_cid := r_class.id;
END IF;
IF v_least_enrolments > v_cur_c_tot_enrolments OR v_least_enrolments = 0
THEN v_least_enrolments := v_cur_c_tot_enrolments; v_least_pop_cid := r_class.id;
END IF;
DBMS_OUTPUT.PUT_LINE('******************************************************************************************');
DBMS_OUTPUT.PUT_LINE('CLASS_ID: ' || r_class.id ||'     '|| 'CLASS_NAME: ' || r_class.name ||'     '||'CAPACITY: ' || r_class.max_attendees ||'     '||'TOTAL_ENROLMENTS: ' || v_cur_c_tot_enrolments);
DBMS_OUTPUT.PUT_LINE(rpad('____________', 12) || lpad('____________', 12) || lpad('____________________', 20) || lpad('____________________', 20) || lpad('____________',12) || lpad('____________',12));
DBMS_OUTPUT.PUT_LINE(rpad('SCHEDULE_ID', 12) || lpad('TRAINER_ID',12) || lpad('START_TIME', 20) || lpad('END_TIME',20) || lpad('ENROLMENTS',12) || lpad('ATTENDANCE',12));
DBMS_OUTPUT.PUT_LINE(rpad('____________', 12) || lpad('____________',12) || lpad('____________________', 20) || lpad('____________________', 20) || lpad('____________',12) || lpad('____________',12));
FOR r_cs IN (select id,to_char(start_time,'DD-MM-YYYY HH24:Mi') as start_time, to_char(end_time,'DD-MM-YYYY HH24:Mi') as end_time, enrolments from class_schedule where class_id = r_class.id order by id)
LOOP
select trainer_id into v_cur_tid from trainer_schedule where event_type='c' and event_id = r_cs.id;
select count(training_session.id) into v_cur_cs_attendance
from training_session, class_schedule
where training_session.attended = 'y' and
training_session.type='c'and
to_char(training_session.start_time,'DD-MM-YYYY HH24:Mi') = to_char(class_schedule.start_time,'DD-MM-YYYY HH24:Mi') and
class_schedule.id = r_cs.id;
DBMS_OUTPUT.PUT_LINE(rpad(r_cs.id, 12) || lpad(v_cur_tid,12) || lpad(r_cs.start_time, 20) || lpad(r_cs.end_time,20) || lpad(r_cs.enrolments,12) || lpad(v_cur_cs_attendance,12));
END LOOP;
END LOOP;
DBMS_OUTPUT.PUT_LINE('******************************************************************************************');
DBMS_OUTPUT.PUT_LINE('******************************************************************************************');
DBMS_OUTPUT.PUT_LINE('MOST_POPULAR_CLASS: '||v_most_pop_cid||'      TOTAL_ENROLMENTS_TO_DATE: '||v_most_enrolments);
DBMS_OUTPUT.PUT_LINE('LEAST_POPULAR_CLASS: '||v_least_pop_cid||'      TOTAL_ENROLMENTS_TO_DATE: '||v_least_enrolments);
DBMS_OUTPUT.PUT_LINE('==================================================================================================================================');
END;
/

Hi,
you could use Dynamic SQL /Execute immediate to run DDL from a stored procedure.
http://download-uk.oracle.com/docs/cd/B10501_01/appdev.920/a96624/11_dynam.htm
Could you please tell why do you want to create a materialized view in stored procedure ?
How frequently you will runt this procedure . It would is better to create a MV once and use it.
thanks

How to generate a view with dynamic name?

I want to generate a view from several tables;
create view sample as select * from book1;
But I hope to create a serial views in my program,that is "sample" maybe "sample20010401" and "sample200010501" ect.If I define a variable,how to pass the value to the view?
Any words are help to me?thanks.
[email protected]
null

Use dynamic SQL
null

How to create materialized view log on remote database

How do you create materialized view logs on a remote database.
I tried
create materialized view log on global_express_views.vccs438_project_work_request@h92edwp with sequence, rowid ( columns...)
ERROR at line 1:
ora-00949 illegal reference to remote database

Hi,
I am not getting the error exactly. But have some suggestion:
If the schema owner does not own the master tables, then the schema owner must have the GLOBAL QUERY REWRITE privilege or the QUERY REWRITE object privilege on each table outside the schema.
Hope, this may help you?
Thanx.. Ratan

How to make materialized view fast refresh parallel

We have Oracle 11.2.0.1 on Redhat 5.2. We use a dozen of fast refresh materialized views in our application.
From time to time MV refresh takes longer time than the refresh interval.
One of way to improve performance of MV refresh is to make the refresh parallel, e.g. http://www.dba-oracle.com/t_materialized_views_refreshing_performance.htm
- Use parallel DML - Oracle author Michael Armstrong Smith notes "I've done parallel materialized view refreshing
on tables recently and improved the load times considerably. Rather than having one load which took 2 hours,
I run 4 parallel loads, one for each partition. The length of time for the whole process is now determined by
how long the biggest partition takes to load. In my case, this is 40 minutes, with two 30 minute loads and one
20 minute load. Overall I am saving 1 hour 20 minutes. I can now add further partitions and do the same thing.
My only limitation is the parallel loads because I don't have unlimited processing power.
{code} My master tables are not partitioned, but think parallel will still better than non-parallel.
Now the question, how to make refresh parallel. According to the paragraph cited above, Use parallel DML appears doing the job. Can someone confirm that.
We use {code}
alter materialied view MV_OFFENSE parallel REFRESH FAST start with sysdate next sysdate+ 1/24;
{code}to schedule refresh. Does the parallel clause here parallels query the MV or refresh the MV?
Any other way to make MV refresh parallel?
Thanks

Doc http://download.oracle.com/docs/cd/E11882_01/server.112/e16579/refresh.htm#i1006319 says:
>
In a data warehousing environment, assuming that the materialized view has a parallel clause, the following sequence of steps is recommended:
1.
Bulk load into the fact table
2.
Enable parallel DML
3.
An ALTER SESSION ENABLE PARALLEL DML statement
4.
Refresh the materialized view

How to Refresh Materialized views

Hi All,
How ro refresh Mv views manualy.could you pls provide definiation for refreshing the MV's manually.
Thanks for your help.

When creating the materialized view, you have the option of specifying whether the refresh occurs manually (ON DEMAND) or automatically (ON COMMIT, DBMS_JOB).
You can use something like:
EXECUTE DBMS_MVIEW.REFRESH('emp_dept_sum','F'); -- 'F' for fast refresh, 'C' for complete refresh
For automatic fast refresh:
CREATE MATERIALIZED VIEW emp_mv
ON PREBUILT TABLE
REFRESH FAST ON COMMIT
ENABLE QUERY REWRITE
AS SELECT empno, ename, dname, loc,
         e.rowid emp_rowid,
         d.rowid dep_rowid
    FROM emp e, dept d
   WHERE e.deptno = d.deptno;

How to change Materialized View query?

Hi all,
sorry for this newbie question, but I'm not able to work out this matter...
How can I change the query used by a materialized view without dropping an recreate all, and using another user(SYS in my case)?
It looks like the command 'alter materialized view ...' does not allow this, am I wrong?
thanks a lot
aldo

You quick answer saved me a lot of other unsuccessfully searches.
thanks
aldo

How to prevent materialized views from refreshing if source table is zero

any ideas?

Probably not what you were hoping for but here are a couple of ideas.
Your account shows - 113 (85 unresolved)
1. How about helping to keep the forum clean by reviewing your 85 unresolved previous questions and giving HELPFUL or ANSWERED credit to those that helped you in the past.
2. Read the FAQ at the top right of the page and post the information about your system and software so that we know what you are working with.
3. Ask your question in the body of the thread. Don't just say 'Any ideas'.
What exactly is your question? Is this an academic question or do you have an actual problem that needs to be addressed?
If you have an actual problem produce the DDL for the materialized view and information about the type of refresh that has been set up for it. Is there a materialized view log on the base table(s)?
The simple answer to your quest is to use REFRESH ON DEMAND and check the base table(s) before you do a manual
refresh. The best answer depends on what version of Oracle you are using and what your actual setup is. Are your
MVs in REFRESH GROUPS?. That can make a difference in the answer.
How can anyone help with this question if you won't provide the information needed(FAQ)? Why SHOULD anyone help if you show you don't appreciate the help by marking questions answered once you have been helped.

How to create materialized view based on a view?

Hi,
I hope this is not very far fetched idea.
I have a very complex view and I would like to replicate it 'in place' that is I would like to make a materialized view that is based on this view complex view. I would like to use this materialized view (i.e table) to query data instead of using the original view, since it takes Oracle some 10-15 seconds to execute my query on the original view and I am not allowed to create indexes on most of the tables that are included in the original view.
Can this be done?
Best regards,
Tamas Szecsy

The best way to do this is to create a materialzed view based on the underlying code of the original view. If you don't have this handy, issue the following in sqlplus:
select text
from user_views
where view_name = 'NAME_OF_VIEW'
You can then cut and paste the sql statement into your create materialized view statement.
Please note, you will probable have to set the long parameter to a higher value to reveal the complete statement for example:
SQL> set long 2048

How to create materialized view based on a synonym

Hi all,
I am trying to create simple materialized view based on a synonym and that synonym is pointing a view in other database (using dblink). I am getting table or view not found error . I am able to select synonym if i use select but not in materialized view. Please help me.
Thanks,

The best way to do this is to create a materialzed view based on the underlying code of the original view. If you don't have this handy, issue the following in sqlplus:
select text
from user_views
where view_name = 'NAME_OF_VIEW'
You can then cut and paste the sql statement into your create materialized view statement.
Please note, you will probable have to set the long parameter to a higher value to reveal the complete statement for example:
SQL> set long 2048

How to CREATE MATERIALIZED VIEW LOG (MV fast refresh) with some JOINS

Hi @ all,
i'm trying to create a MATERIALIZED VIEW LOG for a fast refresh of a MATERIALIZED VIEW.
It works fine with a simple Request in the MATERIALIZED VIEW:
CREATE MATERIALIZED VIEW MV_ZOTD43_P
TABLESPACE GDII
BUILD IMMEDIATE
REFRESH FORCE AS
SELECT * FROM ZOTD43_P;
COMMIT;
CREATE MATERIALIZED VIEW LOG ON ZOTD43_P
TABLESPACE "GDII"
WITH PRIMARY KEY, ROWID, SEQUENCE INCLUDING NEW VALUES;
call DBMS_MVIEW.REFRESH('MV_ZOTD43_P', 'f');
But when I use a complex SQL-Request with some JOINS (one of the Table with spatial Data) in the MATERIALIZED VIEW, I get an error:
CREATE MATERIALIZED VIEW MV_TEST
TABLESPACE GDII
BUILD IMMEDIATE
REFRESH FORCE AS
SELECT lptd04_p.sst_nr AS sst_nr,
lptd03_p.aaaa AS aaaa,
lptd04_geom.geom as geom
FROM lptd04_p lptd04_p
JOIN lptd01_p lptd01_p ON lptd01_p.cre_nr = lptd04_p.sst_nr
JOIN lptd04_geom ON lptd04_geom.sst_nr = lptd04_p.sst_nr
JOIN lptd03_p lptd03_p ON lptd03_p.lief_nr = lptd04_p.lief_nr;
COMMIT;
CREATE MATERIALIZED VIEW LOG ON LPTD04_P
TABLESPACE "GDII"
WITH PRIMARY KEY, ROWID, SEQUENCE INCLUDING NEW VALUES;
call DBMS_MVIEW.REFRESH('MV_TEST', 'f');
Error report:
SQL Error: ORA-12004: REFRESH FAST kann für Materialized View "GDI"."MV_GDI_SST_STAMM" nicht benutzt werden
ORA-06512: in "SYS.DBMS_SNAPSHOT", Zeile 2255
ORA-06512: in "SYS.DBMS_SNAPSHOT", Zeile 2461
ORA-06512: in "SYS.DBMS_SNAPSHOT", Zeile 2430
ORA-06512: in Zeile 1
12004. 00000 - "REFRESH FAST cannot be used for materialized view \"%s\".\"%s\""
*Cause: The materialized view log does not exist or cannot be used. PCT
refresh is also not enabled on the materialized view
*Action: Use just REFRESH, which will reinstantiate the entire table.
If a materialized view log exists and the form of the materialized
view allows the use of a materialized view log or PCT refresh is
possible after a given set of changes, REFRESH FAST will
be available starting the next time the materialized view is
refreshed.
Am I doing something wrong or is it not possible CREATE MATERIALIZED VIEW LOG when the MATERIALIZED VIEW got some JOINS?
Regards,
Greq

Thanks for the link Alessandro ,
the error seems something to do with the Column-Type SDO_GEOMETRY, so
i create a new thread in the Spatial Discussion forum:
FAST REFRESHing of Oracle Materialized Views containing SDO_GEOMETRY column
Regards,
Greq

How to Refresh materialized view

Hi,
I am using 11G owb. I would like to know if any one can help me know if there is any easy to Refresh materialized view . I will be using this materialized view to source data from my maps. this map will be part of a process flow. i would like to refresh the materialized view before every run of the map in process flow.
Thanks,
Ash.
Edited by: user591315 on Aug 6, 2009 1:26 PM

A couple of approaches;
* refresh the MV from a procedure in a pre map process operator (its an operator in a mapping), or
* call the procedure from a process flow activity before the map
Cheers
David

How to generate materialized views?

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