openGauss每日一练第11天 | 学习心得体会 | Create by 朱志浇

课程作业

1.为系统表PG_DATABASE创建视图，重命名视图并修改owner为jim,

CREATE VIEW tdb_view AS
SELECT * FROM PG_DATABASE;

SELECT * FROM tdb_view ;

ALTER VIEW tdb_view RENAME TO tdb_view2;

create user jim password 'zhuzhijiao@123';
alter view tdb_view2 owner to jim;

2.创建一个用户表student，并在用户表上创建视图，修改视图schema;

Create schema tpcds;
CREATE TABLE tpcds.student
(  c_student_sk             integer,   
  c_student_id             char(5),    
  c_first_name              char(6),    
  c_last_name               char(8) 
) ;
INSERT INTO tpcds.student VALUES    
(6885, 1, 'Joes', 'Hunter'),    
(4321, 2, 'Lily','Carter'),    
(9527, 3, 'James', 'Cook'),
(9500, 4, 'Lucy', 'Baker');
CREATE VIEW tpcds.student_details_view_v1 AS
SELECT * FROM tpcds.student
WHERE c_student_sk < 6000;

ALTER VIEW tpcds.student_details_view_v1 SET schema public;

3.使用pg_views查看视图信息

select * from pg_views where schemaname = 'tpcds' or schemaname = 'public';

4.删除视图、表、用户

DROP VIEW tdb_view2;
Drop view student_details_view_v1;
drop table tpcds.student;
drop user jim;

学习心得

通过本次练习，掌握了openGauss视图

视图与基本表不同，是一个虚拟的表。数据库中仅存放视图的定义，而不存放视图对应的数据，这些数据仍存放在原来的基本表中。