lunes, 1 de agosto de 2016
The free feature for Oracle to create materialized views in all release, how to update a materialized view from a trigger
It's called a package
First we have the select, of one or more tables; and the table to store it
Second we create a procedure that insert the query in a table
Third we update it
1) if we want a transactional update, we create a procedure that inserts the values for the new records in the trigger of the tables
2) if we want a log fast refresh, we create a log that stores id of records we want to be updated
3) if we want a full update, we create job
Fourth
For the update process depending the option we have to create a procedure, add to the trigger/job and that all.
Fifth
Aditionally we have a validation procedure that periodically if he found differences can generate a full or partial refresh.
First
Create a package
XXX.PCK_MV_OWNER_TABLE
Procedure:FullRefresh
insert into table
select from tableA,tableB
-- note in this refresh you can put
Procedure:PartialRefreshperTrigger
This must be in a trigger update and or delete
insert into table
select from tableA,tableB
where column=:new.value and column2=:new.value2
Procedure:PartialRefreshperFunction
insert into table
select from tableA,tableB
where not exists in table
Procedure:PartialRefreshperFunction using log
This requires a table that stores ids of modified rows, and a trigger that inserts the rowid when the needed columns of the table are modified, and generates a refresh only of those records in the database.
insert into table
select from tableA,tableB
where not exists in table
Procedure:fast refresh fast
delete from;
FullRefresh;
Procedure:fast refresh online
truncate table;
FullRefresh;
Procedure:validation
with
a select from tableA,tableB
b select fro mtable
select count(*) from
(select from a
minus
select from b
union all
select from b
minus
select from a)
if count>0 then
fullrefresh; -fast or online it dependes on you
end if;
/
Jobs
create job executes validation periodically, depending the tables, etc.
create job if using log to update the materialized view periodically
optionally, create jobs makes partial insert, to reinforce validation.
optionally, makes a full refresh
:)
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