openGauss每日一练第18天 - 学习心得体会

1.创建表，创建普通视图

root@modb:~# su - omm
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 tpcds;
CREATE SCHEMA
omm=# CREATE TABLE tpcds.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(# ) ;
omm=# CREATE TABLE

omm=# INSERT INTO tpcds.customer VALUES    
omm-# omm-# (6885, 1, 'Joes', 'Hunter'),    
(4321, 2, 'Lily','Carter'),    
(9527, 3, 'James', 'Cook'),
omm-# omm-# (9500, 4, 'Lucy', 'Baker');
INSERT 0 4
omm=# omm-# CREATE VIEW tpcds.customer_details_view_v1 AS
SELECT * FROM tpcds.customer
omm-# WHERE c_customer_sk > 5400;
CREATE VIEW
omm=# select * from tpcds.customer_details_view_v1;
          6885 | 1             | Joes         | Hunter  
          9527 | 3             | James        | Cook    
          9500 | 4             | Lucy         | Baker   
(3 rows)

omm=#  c_customer_sk | c_customer_id | c_first_name | c_last_name 
---------------+---------------+--------------+-------------

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2.使用视图创建新的视图

CREATE VIEW
omm=# select * from tpcds.part_view;
 c_customer_sk | c_customer_id | c_first_name | c_last_name 
---------------+---------------+--------------+-------------
          9527 | 3             | James        | Cook    
(1 row)

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3.创建物化视图

NOTICE:  materialized view "mv_test" does not exist, skipping
DROP MATERIALIZED VIEW
omm=# drop table if exists test;
NOTICE:  table "test" does not exist, skipping
DROP TABLE
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)

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4.手动更新物化视图

 schemaname |         viewname         | viewowner |                                             
 definition                                              
------------+--------------------------+-----------+---------------------------------------------
---------------------------------------------------------
 tpcds      | customer_details_view_v1 | omm       | SELECT  * FROM tpcds.customer WHERE (custome
r.c_customer_sk > 5400);
 tpcds      | part_view                | omm       | SELECT  * FROM tpcds.customer_details_view_v
1 WHERE (customer_details_view_v1.c_customer_sk = 9527);
(2 rows)

omm=# select * from GS_MATVIEW;
 matviewid | mapid | ivm | needrefresh | refreshtime 
-----------+-------+-----+-------------+-------------
     16412 |     0 | f   |             | 
(1 row)

omm=# insert into test(testnum) values(generate_series(1,100000));
INSERT 0 100000
omm=# select count(*) from mv_test;
 count 
-------
 50000
(1 row)

omm=#  refresh materialized view mv_test;
REFRESH MATERIALIZED VIEW
omm=#  select count(*) from mv_test;
 count  
--------
 100000
(1 row)

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5.删除创建的视图

omm=# DROP view tpcds.part_view;
DROP VIEW
omm=# DROP view TPCDS.customer_details_view_v1;
DROP VIEW
omm=# DROP MATERIALIZED VIEW mv_test;
DROP MATERIALIZED VIEW
omm=# 
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