openGauss每日一练第6 天 加油

1.创建模式

–创建名为ds的模式

CREATE SCHEMA ds;
omm=# create schema ds;
omm=# CREATE SCHEMA
–查看ds模式信息, owner为omm

\dn+ ds;
omm=# \dn+ ds;
List of schemas
Name | Owner | Access privileges | Description
------±------±------------------±------------
ds | omm | |
(1 row)

2.在ds中建表

create table ds.t1(id int, name char(30));
insert into ds.t1 values(1 ,‘xxxx’);
select * from ds.t1;
omm=# create table ds.t1(id int,name char(30));
CREATE TABLE
omm=# insert into ds.t1 values(1,‘xxxx’);
INSERT 0 1
omm=# select * from ds.t1;
id | name
----±-------------------------------
1 | xxxx
(1 row)
–查看表信息

\d+ ds.t1;
omm=# \d+ ds.t1;
Table “ds.t1”
Column | Type | Modifiers | Storage | Stats target | Description
--------±--------------±----------±---------±-------------±------------
id | integer | | plain | |
name | character(30) | | extended | |
Has OIDs: no
Options: orientation=row, compression=no

3.修改模式信息

–重命名模式为ds_new

ALTER SCHEMA ds RENAME TO ds_new;
select * from ds_new.t1;
omm=# alter schema ds rename to ds_new;
ALTER SCHEMA
omm=# \dn
List of schemas
Name | Owner
-------------±------
cstore | omm
dbe_perf | omm
ds_new | omm
pkg_service | omm
public | omm
snapshot | omm
(6 rows)

omm=# select * from ds_new.t1;
id | name
----±-------------------------------
1 | xxxx
(1 row)
–创建用户jack

CREATE USER jack PASSWORD ‘abcd@123’;
omm=# create user jack password ‘abcd@123’;
NOTICE: The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE

–将ds_new的所有者修改为jack

ALTER SCHEMA ds_new OWNER TO jack;
omm=# alter schema ds_new owner to jack;
ALTER SCHEMA

–查看ds_new模式信息

\dn+ ds_new;
omm=# \dn+ ds_new
List of schemas
Name | Owner | Access privileges | Description
--------±------±------------------±------------
ds_new | jack | |
(1 row)

4.删除模式

DROP SCHEMA ds_new;
–当schema非空时，如果要删除一个schema及其包含的所有对象，需要使用CASCADE关键字

DROP SCHEMA ds_new CASCADE;
DROP USER jack;
omm=# drop schema ds_new cascade;
NOTICE: drop cascades to table ds_new.t1
DROP SCHEMA
omm=# drop user jack;
omm=# DROP ROLE

课后作业

1.创建一个名为tpcds的模式
omm=# create schema tpcds;
CREATE SCHEMA

2.创建一个用户tim, 并将tpcds的owner修改为tim，且修改owner前后分别使用\dn+查看模式信息
omm=# create user tim password ‘abcd.1234’;
NOTICE: The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# alter schema tpcds owner to tim;
ALTER SCHEMA
omm=# \dn+ tpcds;
List of schemas
Name | Owner | Access privileges | Description
-------±------±------------------±------------
tpcds | tim | |
(1 row)

3.重命名tpcds为tpcds1
omm=# alter schema tpcds rename to tpcds1;
ALTER SCHEMA

4.在模式tpcds1中建表customer、插入记录和查询记录
omm=# create table tpcds1.customer(id int,name varchar(30));
CREATE TABLE
omm=# insert into tpcds1.customer values(1,‘abcd’);
INSERT 0 1
omm=# select * from tpcds1.customer;
id | name
----±-----
1 | abcd
(1 row)

5.删除模式tpcds1
omm=# drop table tpcds1.customer;
DROP TABLE
omm=# drop schema tpcds1;
DROP SCHEMA
omm=# drop user tim;
DROP ROLE