openGuass每日一练第4天|学习心得

第四天的学习内容是学习openGauss体系结构，使用多个用户访问同一个数据库。

一、练习环境

实训环境

二、练习内容及实操内容

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;

结果如下：

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=# drop DATABASE  IF EXISTS  musicdb;
NOTICE:  database "musicdb" does not exist, skipping
DROP DATABASE
omm=# drop DATABASE  IF EXISTS  musicdb1;
NOTICE:  database "musicdb1" does not exist, skipping
DROP DATABASE
omm=# drop DATABASE  IF EXISTS  musicdb2;
NOTICE:  database "musicdb2" does not exist, skipping
omm=# DROP DATABASE
drop DATABASE  IF EXISTS  musicdb3;
NOTICE:  database "musicdb3" does not exist, skipping
DROP DATABASE
omm=# drop tablespace IF EXISTS music_tbs;
NOTICE:  Tablespace "music_tbs" does not exist, skipping.
DROP TABLESPACE
omm=# CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb  WITH TABLESPACE = music_tbs;

--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';
 
--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;

--执行下面的命令，查看有哪些用户：
 \du

结果如下：

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

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                                                                                     
                    | {}
 user3     | Sysadmin                                                                                     
                    | {}

 user2     | 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：

分别使用user1、user2、user3访问数据库musicdb2，创建各自的表，并插入数据的操作，可以通过以下sql代码来实现：

--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 products1(product_id INTEGER,product_name char(20),category char(30));
  insert into products1 values(1502,'olympus camera','electrncs');  insert into products1 values(1601,'lamaze','toys');  insert into products1 values(1700,'wait interface','Books');  insert into products1 values(1666,'harry potter','toys');
  select * from products1;
 
--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 products2(product_id INTEGER,product_name char(20),category char(30));
  insert into products2 values(1502,'olympus camera','electrncs');
  insert into products2 values(1601,'lamaze','toys');
  insert into products2 values(1700,'wait interface','Books');
  insert into products2 values(1666,'harry potter','toys');
  select * from products2;


--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 products3(product_id INTEGER,product_name char(20),category char(30));  insert into products3 values(1502,'olympus camera','electrncs');
  insert into products3 values(1601,'lamaze','toys');
  insert into products3 values(1700,'wait interface','Books');
  insert into products3 values(1666,'harry potter','toys');
  select * from products3;

结果如下：

omm=# create table products1(product_id INTEGER,product_name char(20),category char(30));
omm=# CREATE TABLE
  insert into products1 values(1502,'olympus camera','electrncs');
INSERT 0 1
omm=#   select * from products1;
(1 row)

omm=#  product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     

musicdb=> create table products2(product_id INTEGER,product_name char(20),category char(30));
CREATE TABLE
musicdb=>   insert into products2 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb=>   insert into products2 values(1601,'lamaze','toys');
INSERT 0 1
musicdb=>   insert into products2 values(1700,'wait interface','Books');
INSERT 0 1
musicdb=>   insert into products2 values(1666,'harry potter','toys');
INSERT 0 1
  select * from products2;musicdb=> 
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(4 rows)

musicdb=> 

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 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb=>   insert into products3 values(1601,'lamaze','toys');
INSERT 0 1
musicdb=>   insert into products3 values(1700,'wait interface','Books');
INSERT 0 1
musicdb=>   insert into products3 values(1666,'harry potter','toys');
INSERT 0 1
musicdb=>   select * from products3;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(4 rows)

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

可以通过以下的sql命令查阅：

\dt 

结果如下：

musicdb=>  \dt                     
                           List of relations
 Schema |   Name    | Type  | Owner |             Storage              
--------+-----------+-------+-------+----------------------------------
 public | product2  | table | user2 | {orientation=row,compression=no}
 public | products2 | table | user2 | {orientation=row,compression=no}
 public | products3 | table | user3 | {orientation=row,compression=no}
(3 rows)

musicdb=> 

三、总结