openGauss每日一练第4天 | 一个数据库可以被多个用户访问

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

omm@modb:~$ gs_ctl status
[2022-11-27 20:25:30.469][382][][gs_ctl]: gs_ctl status,datadir is /var/lib/opengauss/data 
gs_ctl: server is running (PID: 1)
/usr/local/opengauss/bin/gaussdb
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
omm=#       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     | 
omm=#  template0 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
 template1 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
(4 rows)

--进入数据库omm，创建表空间、测试数据库
omm=# CREATE TABLESPACE music_tbs2 RELATIVE LOCATION 'tablespace/music_tbs2';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb2 WITH TABLESPACE = music_tbs2;
CREATE DATABASE

--执行下面的SQL语句，创建用户user1、user2、user3：
omm=#  CREATE USER user1 IDENTIFIED BY 'kunpeng@2022';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=#  CREATE USER user2 IDENTIFIED BY 'kunpeng@2022';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=#  CREATE USER user3 IDENTIFIED BY 'kunpeng@2022';
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;
omm=# ALTER ROLE
ALTER USER user3 SYSADMIN;
ALTER ROLE

--执行下面的命令，查看有哪些用户：
omm=# \du
                                                              List of roles
 Role name |                                                    Attributes                                                    | M
ember of 
-----------+------------------------------------------------------------------------------------------------------------------+--
---------
 gaussdb   | Sysadmin                                                                                                         | {
}
 omm       | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, UseFT | {
}
 user1     | Sysadmin                                                                                                         | {
}
 user2     | Sysadmin                                                                                                         | {
}
 user3     | Sysadmin                                                                                                         | {
}

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：

--执行下面的SQL语句，创建用户user1、user2、user3：
--以用户user1的身份在数据库musicdb2中创建表products1，并插入一条数据：
omm=#  \c musicdb2 user1
Password for user user1: 
musicdb2=> Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb2" as user "user1".

musicdb2=>   create table products1(product_id integer,product_name char(20),category char(30));
CREATE TABLE

musicdb2=>   insert into products1 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb2=>   select * from products1;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
(1 row)
 
--以用户user2的身份在数据库musicdb2中创建表products2，并插入一条数据：
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(1601,'lamaze','toys');
INSERT 0 1
musicdb2=>   select * from products2;
musicdb2=>  product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1601 | lamaze               | toys                          
(1 row)


--以用户user3的身份在数据库musicdb2中创建表products3，并插入一条数据：
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(1700,'wait interface','Books');
INSERT 0 1
musicdb2=>   insert into products3 values(1666,'harry potter','toys');
INSERT 0 1
musicdb2=>   select * from products3;
 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

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)