openGuass每日一练第5天|学习心得

第五天的学习内容主要是学习openGauss体系结构，使用一个用户访问多个数据库。

一、练习环境

实训环境

二、练习内容及课程作业

本章学习内容是数据库用户user1可以访问不同的数据库（musicdb1、musicdb2、musicdb3）。

实验中user1用户在数据库musicdb1中创建了表t11、在数据库musicdb2创建了表t21、在数据库musicdb3中创建了表t31，验证了这个结论。

通过学习的内容完成以下的4个作业。在完成作业之前，需要准备测试环境

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 musicdb1  WITH TABLESPACE = music_tbs;
CREATE DATABASE musicdb2  WITH TABLESPACE = music_tbs;
CREATE DATABASE musicdb3  WITH TABLESPACE = music_tbs;

--执行下面的SQL语句，创建用户user1：

 CREATE USER user1 IDENTIFIED BY 'kunpeng@1234';
 
--授予user1数据库系统的SYSADMIN权限：

ALTER USER user1 SYSADMIN;

具体结果如下：

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;
omm=# NOTICE:  database "musicdb1" does not exist, skipping
DROP DATABASE
drop DATABASE  IF EXISTS  musicdb2;
DROP DATABASE
omm=# NOTICE:  database "musicdb2" does not exist, skipping
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=# 

omm=# CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb1  WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# CREATE DATABASE musicdb2  WITH TABLESPACE = music_tbs;

CREATE DATABASE
omm=# CREATE DATABASE musicdb3  WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# 

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

1.创建数据库musicdb10，创建用户user10，赋予sysadmin权限

完成以上操作，只需要输入以下的sql命令

CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE DATABASE musicdb10  WITH TABLESPACE = music_tbs;CREATE USER user10 IDENTIFIED BY 'kunpeng@1234';
ALTER USER user10 SYSADMIN;

结果如下：

omm=# CREATE DATABASE musicdb10  WITH TABLESPACE = music_tbs;

CREATE DATABASE
omm=# CREATE USER user10 IDENTIFIED BY 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# ALTER USER user10 SYSADMIN;
ALTER ROLE
omm=# 

2.用户user10访问数据库postgres，创建一个表并插入数据

完成以上操作，只需要输入以下的sql命令

--用户user10登录到数据库postgres，创建表t11，并插入、查看数据

 \c postgres user10

 create table t11(col1 char(20));
 insert into t11 values('Hello openGauss! 11');
 select * from t11;      

结果如下：

omm=#  \c postgres user10
Password for user user10: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "postgres" as user "user10".
openGauss=>  create table t11(col1 char(20));
CREATE TABLE
openGauss=>  insert into t11 values('Hello openGauss! 11');
INSERT 0 1
openGauss=>  select * from t11;
         col1         
----------------------
 Hello openGauss! 11 
(1 row)

openGauss=> 

3.用户user10访问数据库omm，创建一个表并插入数据

完成以上操作，只需要输入以下的sql命令

\c omm user10

 create table om1(col1 char(20));
 insert into om1 values('Hello openGauss! om1');
 select * from om1; 

结果如下：

openGauss=> \c omm user10
Password for user user10: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "user10".
omm=> create table om1(col1 char(20));
CREATE TABLE
omm=>  insert into om1 values('Hello openGauss! om1');
INSERT 0 1
omm=>  select * from om1; 
         col1         
----------------------
 Hello openGauss! om1
(1 row)

omm=> 

4.用户user10访问数据库musicdb10，创建一个表并插入数据

完成以上操作，只需要输入以下的sql命令

\c musicdb10 user10

 create table mb1(col1 char(20));
 insert into mb1 values('Hello openGauss! mb1');
 select * from mb1; 

结果如下：

omm=> \c musicdb10 user10
Password for user user10: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb10" as user "user10".
musicdb10=>  create table mb1(col1 char(20));
CREATE TABLE
musicdb10=>  insert into mb1 values('Hello openGauss! mb1');
INSERT 0 1
musicdb10=>  select * from mb1; 
         col1         
----------------------
 Hello openGauss! mb1
(1 row)

musicdb10=> 

三、总结