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。

作业练习

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

root@modb:~# su - omm
omm@modb:~$ gsql -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr  )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.

omm=# \db
      List of tablespaces
    Name    | Owner | Location 
------------+-------+----------
 pg_default | omm   | 
 pg_global  | omm   | 
(2 rows)

omm=# \l
                         List of databases
   Name    | Owner | Encoding | Collate | Ctype | Access privileges 
-----------+-------+----------+---------+-------+-------------------
 omm       | omm   | UTF8     | C       | C     | 
 postgres  | omm   | UTF8     | C       | C     | 
 template0 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
 template1 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
(4 rows)

omm=# CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb2 WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=#  CREATE USER user1 IDENTIFIED BY 'xiaocx@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=#  CREATE USER user2 IDENTIFIED BY 'xiaocx@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=#  CREATE USER user3 IDENTIFIED BY 'xiaocx@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user2 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user3 SYSADMIN;
ALTER ROLE
omm=# \du
                                                              List of roles
 Role name |                                                    Attributes                                                    | Member of 
-----------+------------------------------------------------------------------------------------------------------------------+-----------
 gaussdb   | Sysadmin                                                                                                         | {}
 omm       | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, UseFT | {}
 user1     | Sysadmin                                                                                                         | {}
 user2     | Sysadmin                                                                                                         | {}
 user3     | Sysadmin                                                                                                         | {}

omm=# 

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：

-- 用户user1访问数据库musicdb2 ，然后创建表并插入数据
musicdb=> \c musicdb2 user1
Password for user user1: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb2" as user "user1".
musicdb2=> 
musicdb2=>  create table products1(product_id INTEGER,product_name char(20),category Char(30));
musicdb2=> CREATE TABLE
musicdb2=> insert into products1 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb2=> insert into products1 values(1601,'lamaze','toys');
INSERT 0 1
musicdb2=> insert into products1 values(1601,'wait interface','Books');
INSERT 0 1
musicdb2=>  insert into products1 values(1601,'harry potter','toys');
INSERT 0 1
musicdb2=> select * from products1;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
       1601 | wait interface       | Books                         
       1601 | harry potter         | toys                          
(4 rows)

musicdb2=> -- 用户user2访问数据库musicdb2 ，然后创建表并插入数据

musicdb2=> \c musicdb2 user2
Password for user user2: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb2" as user "user2".
musicdb2=> create table products2(product_id INTEGER,product_name char(20),category Char(30));
CREATE TABLE
musicdb2=> insert into products2 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb2=> insert into products2 values(1601,'lamaze','toys');
INSERT 0 1
musicdb2=> insert into products2 values(1601,'wait interface','Books');
INSERT 0 1
musicdb2=> insert into products2 values(1601,'harry potter','toys');
INSERT 0 1
musicdb2=> select * from products2;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
       1601 | wait interface       | Books                         
       1601 | harry potter         | toys                          
(4 rows)

musicdb2=> -- 用户user3访问数据库musicdb2 ，然后创建表并插入数据
musicdb2=> \c musicdb2 user3
Password for user user3: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb2" as user "user3".
musicdb2=> create table products3(product_id INTEGER,product_name char(20),category Char(30));
CREATE TABLE
musicdb2=> insert into products3 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb2=> insert into products3 values(1601,'lamaze','toys');
INSERT 0 1
musicdb2=> insert into products3 values(1601,'wait interface','Books');
INSERT 0 1
musicdb2=> insert into products3 values(1601,'harry potter','toys');
INSERT 0 1                         
musicdb2=> select * from products3;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
       1601 | wait interface       | Books                         
       1601 | harry potter         | toys                          
(4 rows)

musicdb2=> 

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

musicdb2=> \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)