今日的学习目标：
学习openGauss视图
今日的学习体会：
掌握openGauss相关操作，与其他数据库的视图操作方法一致，比较简单。
今日的学习步骤：
课程学习
连接openGauss
su - omm
gsql -r
1.创建视图
–为系统表pg_tablespace创建字段spcname为pg_default组成的视图
CREATE VIEW tps_view AS
SELECT * FROM pg_tablespace WHERE spcname = ‘pg_default’;
–查看视图
SELECT * FROM tps_view ;
–创建一个由c_customer_sk小于6000的内容组成的视图
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’);
CREATE VIEW tpcds.customer_details_view_v1 AS
SELECT * FROM tpcds.customer
WHERE c_customer_sk < 6000;
–查看视图
select * from tpcds.customer_details_view_v1;
–系统视图
select * from pg_views where schemaname = ‘tpcds’ or schemaname = ‘public’;
2.修改视图定义
–修改视图名称
ALTER VIEW tpcds.customer_details_view_v1 RENAME TO customer_details_view_v2;
–修改视图所属schema
ALTER VIEW tpcds.customer_details_view_v2 SET schema public;
–修改视图owner
create user jack password ‘abcd@123’;
alter view tps_view owner to jack;
–查看系统视图tps_views
select * from pg_views where viewname = ‘customer_details_view_v2’ or viewname = ‘tps_view’;
3.删除视图
DROP VIEW customer_details_view_v2;
Drop view tps_view;
