openGauss每日一练第6天

学习地址

https://www.modb.pro/course/133

学习目标

学习 openGauss 创建模式、修改模式属性和删除模式

模式是一组数据库对象的集合，主要用于控制对数据库对象的访问

课后作业

1.创建一个名为 tpcds 的模式

SQL文本：

create schema tpcds;

\dn tpcds

omm=# create schema tpcds;

CREATE SCHEMA

omm=# \dn tpcds

List of schemas

Name | Owner

-------+-------

tpcds | omm

(1 row)

omm-#

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

SQL文本：

create user tim password '_*';

\dn+

alter schema tpcds owner to tim;

\dn+

omm=# create user tim password '_*';

omm=# CREATE ROLE

omm=# \dn+

List of schemas

Name | Owner | Access privileges | Description

-------------+-------+-------------------+----------------------------------

cstore | omm | | reserved schema for DELTA tables

dbe_perf | omm | | dbe_perf schema

pkg_service | omm | | pkg_service schema

public | omm | omm=UC/omm +| standard public schema

| | =U/omm |

schema2 | omm | |

snapshot | omm | | snapshot schema

tim | tim | |

tpcds | omm | |

(8 rows)

omm=# alter schema tpcds owner to tim;

ALTER SCHEMA

omm=# \dn+

List of schemas

Name | Owner | Access privileges | Description

-------------+-------+-------------------+----------------------------------

cstore | omm | | reserved schema for DELTA tables

dbe_perf | omm | | dbe_perf schema

pkg_service | omm | | pkg_service schema

public | omm | omm=UC/omm +| standard public schema

| | =U/omm |

schema2 | omm | |

snapshot | omm | | snapshot schema

tim | tim | |

tpcds | tim | |

(8 rows)

omm=#

3.重命名 tpcds 为 tpcds1

SQL文本：

alter schema tpcds rename to tpcds1;

\dn+

omm=# alter schema tpcds rename to tpcds1;

ALTER SCHEMA

omm=# \dn+

List of schemas

Name | Owner | Access privileges | Description

-------------+-------+-------------------+----------------------------------

cstore | omm | | reserved schema for DELTA tables

dbe_perf | omm | | dbe_perf schema

pkg_service | omm | | pkg_service schema

public | omm | omm=UC/omm +| standard public schema

| | =U/omm |

schema2 | omm | |

snapshot | omm | | snapshot schema

tim | tim | |

tpcds1 | tim | |

(8 rows)

omm=#

4.在模式 tpcds1 中建表 customer、插入记录和查询记录

SQL文本：

建表

create table tpcds1.customer

( c_customer_sk integer,

c_customer_id char(5),

c_first_name char(6),

c_last_name char(8)

);

插入记录

INSERT INTO tpcds1.customer (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES

(6885, 1, 'Joes', 'Hunter'),

(4321, 2, 'Lily','Carter'),

(9527, 3, 'James', 'Cook'),

(9500, 4, 'Lucy', 'Baker');

查询记录

select * from tpcds1.customer;

omm=# create table tpcds1.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=# INSERT INTO tpcds1.customer (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES

omm-# (6885, 1, 'Joes', 'Hunter'),

omm-# (4321, 2, 'Lily','Carter'),

omm-# (9527, 3, 'James', 'Cook'),

omm-# (9500, 4, 'Lucy', 'Baker');

INSERT 0 4

omm=# select * from tpcds1.customer;

c_customer_sk | c_customer_id | c_first_name | c_last_name

---------------+---------------+--------------+-------------

6885 | 1 | Joes | Hunter

4321 | 2 | Lily | Carter

9527 | 3 | James | Cook

9500 | 4 | Lucy | Baker

(4 rows)

omm=# \dt customer

List of relations

Schema | Name | Type | Owner | Storage

--------+----------+-------+-------+----------------------------------

tpcds1 | customer | table | omm | {orientation=row,compression=no}

(1 row)

omm=#

5.删除模式 tpcds1

SQL文本： drop schema tpcds1; drop schema tpcds1 cascade; \dn+

omm=# drop schema tpcds1;

ERROR: cannot drop schema tpcds1 because other objects depend on it

DETAIL: table customer depends on schema tpcds1

HINT: Use DROP ... CASCADE to drop the dependent objects too.

omm=# drop schema tpcds1 cascade;

NOTICE: drop cascades to table customer

DROP SCHEMA

omm=# \dn+

List of schemas

Name | Owner | Access privileges | Description

-------------+-------+-------------------+----------------------------------

cstore | omm | | reserved schema for DELTA tables

dbe_perf | omm | | dbe_perf schema

pkg_service | omm | | pkg_service schema

public | omm | omm=UC/omm +| standard public schema

| | =U/omm |

schema2 | omm | |

snapshot | omm | | snapshot schema

tim | tim | |

(7 rows)

omm=#