Interpretation of oracleday2

interpretation oracleday2 oracleday

– Create a simple view
create view view_owners1 as
select * from t_owners where ownertypeid=1

– Query simple view
select * from view_owners1 where addressid=1

– Modify view data
update view_owners1 set name=‘ Fan Xiaobing ’ where id=1;
commit;

select * from t_owners

– View with check constraint
create view view_address2 as
select * from t_address where areaid=2
with check option

– The successful statement cannot be modified , Because the condition of this view is areaid=2
update view_address2 set areaid=3 where id=4

– Read only view
create or replace view view_owners1 as
select * from t_owners where ownertypeid=1
with read only

– Modify read-only view data
update view_owners1 set name=‘ Fan Dabing ’ where id=1;

– Create a view with errors
create force view view_test as
select * from t_test

– Complex view - More than a table
create or replace view view_owners as
select ow.id Owner number ,ow.name Name of employer ,ot.name Type of owner from t_owners ow,t_ownertype ot
where ow.ownertypeid=ot.id

– Query complex views ( More than a table )
select * from view_owners where Type of owner =‘ Resident ’;

– Modify complex views ( More than a table ) The data of
update view_owners set Name of employer =‘ Lin Lingling ’ where Owner number =4

update view_owners set Type of owner =‘ business ’ where Owner number =4

– Key retention table : The table that retains the primary key

– A complex view of aggregate statistics
create view view_accountsum as
select year,month,sum(money) money
from t_account
group by year,month
order by year,month

select * from view_accountsum where year=‘2012’ and month=‘03’
– Can you modify it ?– answer : Cannot .
update view_accountsum set month=‘04’ where year=‘2012’ and month=‘03’

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