学习目标

学习openGauss体系结构，使用多个用户访问同一个数据库

课程学习

创建user1、user2、user3用户，验证数据库musicdb可以被用户user1、user2、user3访问（分别在数据库中创建了一张表、插入数据、进行查询）。即一个数据库可以被多个用户访问。

课后作业

–进入数据库omm，创建表空间、测试数据库

CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE DATABASE musicdb  WITH TABLESPACE = music_tbs;

1.创建用户user1、user2、user3，授予user1、user2、user3数据库系统的SYSADMIN权限

--创建用户user1、user2、user3
omm=# CREATE USER user1 IDENTIFIED BY 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# CREATE USER user2 IDENTIFIED BY 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=#  CREATE USER user3 IDENTIFIED BY 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
--授予user1、user2、user3数据库系统的SYSADMIN权限：
omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user2 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user3 SYSADMIN;
ALTER ROLE

2.分别使用user1、user2、user3访问数据库musicdb2，创建各自的表，并插入数据。表名和数据如下：

表名分别为： products1、 products2、 products3

向表中插入数据：

 --以用户user1的身份在数据库musicdb中创建表products1，并插入数据：
 切换用户 ------- \c musicdb user1
omm=# \c musicdb user1
Password for user user1: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user1".
musicdb=>
musicdb=> CREATE TABLE products1 ( product_id integer,product_name char(20),category char(30));
musicdb=> CREATE TABLE
musicdb=> INSERT INTO products1 (product_id,product_name,category) VALUES (1502,'olympus camera','electrncs');
musicdb=> INSERT 0 1
musicdb=> 
musicdb=> INSERT INTO products1 (product_id,product_name,category) VALUES (1601,'lamaze','toys');
INSERT 0 1
musicdb=> INSERT INTO products1 (product_id,product_name,category) VALUES (1700,'wait interface','Books');
INSERT 0 1
musicdb=> INSERT INTO products1 (product_id,product_name,category) VALUES (1666,'harry potter','toys');
INSERT 0 1
musicdb=> select * from products1;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(4 rows)
--------------------------------------------------------------------------------------
--以用户user2的身份在数据库musicdb中创建表products2，并插入数据：
切换用户 ------- \c musicdb user2
musicdb=> \c musicdb user2
Password for user user2: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user2".
musicdb=> 
musicdb=> CREATE TABLE products2 ( product_id integer,product_name char(20),category char(30));
CREATE TABLE
musicdb=> INSERT INTO products2 (product_id,product_name,category) VALUES (1502,'olympus camera','electrncs');
musicdb=> INSERT 0 1
musicdb=> INSERT INTO products2 (product_id,product_name,category) VALUES (1601,'lamaze','toys');
INSERT 0 1
musicdb=> select * from products2;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
(2 rows)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
--以用户user3的身份在数据库musicdb中创建表products3，并插入数据：
切换用户 ------- \c musicdb user3
musicdb=> \c musicdb user3
Password for user user3: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user3".
musicdb=> CREATE TABLE products3 ( product_id integer,product_name char(20),category char(30));
CREATE TABLE
musicdb=> INSERT INTO products3 (product_id,product_name,category) VALUES (1700,'wait interface','Books');
INSERT 0 1
musicdb=> INSERT INTO products3 (product_id,product_name,category) VALUES (1666,'harry potter','toys');
INSERT 0 1
musicdb=> select * from products3;
musicdb=>  product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(2 rows)

3.使用user1、user2、user3用户中的任何一个，查看当前数据库musicdb2有哪些表

musicdb=> \c musicdb user1
Password for user user1: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user1".
musicdb=> \dt
                           List of relations
 Schema |   Name    | Type  | Owner |             Storage              
--------+-----------+-------+-------+----------------------------------
 public | products1 | table | user1 | {orientation=row,compression=no}
 public | products2 | table | user2 | {orientation=row,compression=no}
 public | products3 | table | user3 | {orientation=row,compression=no}
(3 rows)

musicdb=> \c musicdb user2
Password for user user2: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user2".
musicdb=> \dt
                           List of relations
 Schema |   Name    | Type  | Owner |             Storage              
--------+-----------+-------+-------+----------------------------------
 public | products1 | table | user1 | {orientation=row,compression=no}
 public | products2 | table | user2 | {orientation=row,compression=no}
 public | products3 | table | user3 | {orientation=row,compression=no}
(3 rows)
omm=# \c musicdb user3
Password for user user3: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user3".
musicdb=> \dt
                           List of relations
 Schema |   Name    | Type  | Owner |             Storage              
--------+-----------+-------+-------+----------------------------------
 public | products1 | table | user1 | {orientation=row,compression=no}
 public | products2 | table | user2 | {orientation=row,compression=no}
 public | products3 | table | user3 | {orientation=row,compression=no}
(3 rows)

musicdb=>