openGauss每日一练第18天 | 学习💯

课程作业

1.创建表，创建普通视图

--创建模式、表和插入数据
su - omm
sql -r
Create schema tpcds;
CREATE TABLE tpcds.customer
(  c_customer_sk             integer,   
  c_customer_id             char(5),    
  c_first_name              char(6),    
  c_last_name               char(8) 
) ;
INSERT INTO tpcds.customer VALUES    
(6885, 1, 'Joes', 'Hunter'),    
(4321, 2, 'Lily','Carter'),    
(9527, 3, 'James', 'Cook'),
(9500, 4, 'Lucy', 'Baker');
--创建视图
CREATE VIEW tpcds.customer_details_view_v1 AS
SELECT * FROM tpcds.customer WHERE c_customer_sk > 5400;
--查看视图内容
select * from tpcds.customer_details_view_v1;
复制

2.使用视图创建新的视图

create  VIEW tpcds.part_view as  SELECT * FROM  tpcds.customer_details_view_v1 where  c_customer_sk =9527;
 --查看新的视图
select * from tpcds.part_view;
复制

3.创建物化视图

--创建基表
drop materialized view if exists mv_test;
drop table if exists test;
create table test(id serial primary key,testnum serial);
insert into test(testnum) values(generate_series(1,100000));
--创建物化视图：
create materialized view mv_test as select * from test where testnum%2=0;
--查看物化视图目前有多少行记录：
select count(*) from mv_test;
复制

4.手动更新物化视图

--向基表test插入数据，查看物化视图有多少行记录：
insert into test(testnum) values(generate_series(1,100000));
select count(*) from mv_test;
--手动更新物化视图，并查看更新物化视图后，物化视图有多少行记录：
refresh materialized view mv_test;
select count(*) from mv_test;
复制

5.删除创建的视图

--删除普通视图
DROP view tpcds.part_view;
DROP view TPCDS.customer_details_view_v1;
--删除物化视图
DROP MATERIALIZED VIEW mv_test;
复制