课程作业

1.创建表，创建普通视图

omm@modb:~$ gsql -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr  )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.

omm=# create schema viewdb;
CREATE SCHEMA
omm=# create table viewdb.customer
omm-# (  c_customer_sk             integer,   
omm(#   c_customer_id             char(5),    
omm(#   c_first_name              char(6),    
omm(#   c_last_name               char(8) 
omm(# ) ;
CREATE TABLE
omm=# CREATE VIEW viewdb.customer_details_view_v1 AS
omm-# SELECT * FROM viewdb.customer
omm-# WHERE c_customer_sk > 5400;
CREATE VIEW
omm=# select * from viewdb.customer_details_view_v1;
c_customer_sk | c_customer_id | c_first_name | c_last_name 
---------------+---------------+--------------+-------------
      6885 | 1             | Joes         | Hunter  
      9527 | 3             | James        | Cook    
      9500 | 4             | Lucy         | Baker   
(3 rows)

2.使用视图创建新的视图

3.创建物化视图

omm=# create table test(id serial primary key,testnum serial);
NOTICE:  CREATE TABLE will create implicit sequence "test_id_seq" for serial column "test.id"
NOTICE:  CREATE TABLE will create implicit sequence "test_testnum_seq" for serial column "test.testnum"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "test_pkey" for table "test"
CREATE TABLE
omm=# insert into test(testnum) values(generate_series(1,100000));
INSERT 0 100000
omm=# create materialized view mv_test as 
omm-# select * from test where testnum%2=0;
CREATE MATERIALIZED VIEW
omm=# select count(*) from mv_test;
count 
-------
50000
(1 row)

omm=# 

4.手动更新物化视图

5.删除创建的视图

--删除物化视图
omm=# DROP MATERIALIZED VIEW mv_test;
DROP MATERIALIZED VIEW
omm=# 
--删除普通视图