第4天 | openGauss中一个数据库可以被多个用户访问

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。

课程作业

#测试环境准备
su - omm
gsql -r
--进入数据库omm，创建表空间、测试数据库
drop DATABASE  IF EXISTS  musicdb;
drop DATABASE  IF EXISTS  musicdb1;
drop DATABASE  IF EXISTS  musicdb2;
drop DATABASE  IF EXISTS  musicdb3;
drop tablespace IF EXISTS music_tbs;

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
#--执行下面的SQL语句，创建用户user1、user2、user3：

 CREATE USER user1 IDENTIFIED BY 'kunpeng@1234';
 CREATE USER user2 IDENTIFIED BY 'kunpeng@1234';
 CREATE USER user3 IDENTIFIED BY 'kunpeng@1234';
 
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：

ALTER USER user1 SYSADMIN;
ALTER USER user2 SYSADMIN;
ALTER USER user3 SYSADMIN;

omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE
omm=# 
omm=# ALTER USER user2 SYSADMIN;
ALTER ROLE
omm=# 
omm=# ALTER USER user3 SYSADMIN;
ALTER ROLE

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

 #--以用户user1的身份在数据库musicdb中创建表t1，并插入一条数据：
 \c musicdb user1
  
  create table t1(col1 char(20));
  insert into t1 values('Hello kunpeng 1');
  select * from t1;
 
 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 t1(col1 char(20));
CREATE TABLE
musicdb=> insert into t1 values('Hello kunpeng 1');
INSERT 0 1
musicdb=>  select * from t1;
         col1         
----------------------
 Hello kunpeng 1     
(1 row)
 
--以用户user2的身份在数据库musicdb中创建表t2，并插入一条数据：
  \c musicdb user2

  create table t2(col1 char(20));
  insert into t2 values('Hello kunpeng 2');
  select * from t2;
omm=# \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=>   create table t2(col1 char(20));
CREATE TABLE
musicdb=>   insert into t2 values('Hello kunpeng 2');
INSERT 0 1
musicdb=>   select * from t2;
         col1         
----------------------
 Hello kunpeng 2     
(1 row)


--以用户user3的身份在数据库musicdb中创建表t3，并插入一条数据：
  \c musicdb user3

  create table t3(col1 char(20));
  insert into t3 values('Hello kunpeng 3');
  select * from t3;
  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=> 
musicdb=> 
musicdb=> create table t3(col1 char(20));
CREATE TABLE
musicdb=>   insert into t3 values('Hello kunpeng 3');
INSERT 0 1
musicdb=>   select * from t3;
         col1         
----------------------
 Hello kunpeng 3     
(1 row)

musicdb=> 

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

#使用user1、user2、user3用户中的任何一个，执行如下命令，查看当前数据库musicdb有哪些表：

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=> \dt
                        List of relations
 Schema | Name | Type  | Owner |             Storage              
--------+------+-------+-------+----------------------------------
 public | t1   | table | user1 | {orientation=row,compression=no}
 public | t2   | table | user2 | {orientation=row,compression=no}
 public | t3   | table | user3 | {orientation=row,compression=no}
(3 rows)

musicdb=> 
musicdb=>