openGauss每日一练第5天 一个用户可以访问多个数据库

学习目标

学习openGauss体系结构，使用一个用户访问多个数据库。

课程学习

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。

课程作业

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

--创建数据库musicdb10（包括创建表空间）
/*
DROP DATABASE   IF EXISTS  musicdb10;
DROP TABLESPACE IF EXISTS  musicdb10_tbs;

CREATE TABLESPACE musicdb10_tbs RELATIVE LOCATION 'tablespace/test_ts10';
CREATE DATABASE musicdb10 WITH TABLESPACE = musicdb10_tbs;
*/

!> \c omm
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "omm" via socket in "/tmp" at port "5432".
omm=# DROP DATABASE   IF EXISTS  musicdb10;
NOTICE:  database "musicdb10" does not exist, skipping
DROP DATABASE
omm=# DROP TABLESPACE IF EXISTS  musicdb10_tbs;
NOTICE:  Tablespace "musicdb10_tbs" does not exist, skipping.
omm=# DROP TABLESPACE
CREATE TABLESPACE musicdb10_tbs RELATIVE LOCATION 'tablespace/test_ts10';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb10 WITH TABLESPACE = musicdb10_tbs;
CREATE DATABASE

--查看musicdb10信息
omm=#  \l
                         List of databases
   Name    | Owner | Encoding | Collate | Ctype | Access privileges 
-----------+-------+----------+---------+-------+-------------------
 music_db  | omm   | UTF8     | C       | C     | 
 music_db1 | omm   | UTF8     | C       | C     | 
 music_db2 | omm   | UTF8     | C       | C     | 
 musicdb   | omm   | UTF8     | C       | C     | 
 musicdb1  | omm   | UTF8     | C       | C     | 
 musicdb10 | omm   | UTF8     | C       | C     | 
 musicdb2  | omm   | UTF8     | C       | C     | 
 musicdb3  | omm   | UTF8     | C       | C     | 
 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
(12 rows)

--创建用户user1：
omm=# DROP user IF EXISTS user10;
NOTICE:  role "user10" does not exist, skipping
DROP ROLE
omm=# CREATE USER user10 IDENTIFIED BY 'meiriyilian@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=#  

--授予user10数据库系统的SYSADMIN权限：
omm=# ALTER USER user10 SYSADMIN;
ALTER ROLE

--查看user10信息
omm=# \du+
omm=#                              List of roles
 Role name |                                                    Attributes                                              
      | Member of | Description 
-----------+------------------------------------------------------------------------------------------------------------
 user10    | Sysadmin                                                                                                   
      | {}        | 
------+-----------+-------------
 gaussdb   | Sysadmin                                                                                                   
      | {}        | 
 omm       | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin

2.用户user10访问数据库postgres，创建一个表并插入数据

--用户user10登录到数据库postgres，创建表test05，并插入、查看数据
/*
 \c postgres user10

 create table test05(id integer, comm char(20));
 insert into test05 values(1, 'Hello world!');
 select * from test05 ;   
*/


openGauss=> \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 test05(id integer, comm char(20));
CREATE TABLE
openGauss=> insert into test05 values(1, 'Hello world!');
INSERT 0 1
openGauss=> select * from test05 ;  
openGauss=>  id |         comm         
----+----------------------
  1 | Hello world!        
(1 row)

3.用户user10访问数据库omm，创建一个表并插入数据

--用户user10登录到数据库omm，创建表test05，并插入、查看数据
/*
 \c omm user10

 create table test05(id integer, comm char(20));
 insert into test05 values(1, 'Hello world!');
 select * from test05 ;   
*/

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 test05(id integer, comm char(20));
CREATE TABLE
omm=>  insert into test05 values(1, 'Hello world!');
INSERT 0 1
omm=>  select * from test05 ;   
 id |         comm         
----+----------------------
  1 | Hello world!        
(1 row)

4.用户user10访问数据库musicdb10，创建一个表并插入数据

--用户user10登录到数据库musicdb10，创建表test05，并插入、查看数据
/*
 \c musicdb10 user10

 create table test05(id integer, comm char(20));
 insert into test05 values(1, 'Hello world!');
 select * from test05 ;   
*/

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=> 
musicdb10=>  create table test05(id integer, comm char(20));
CREATE TABLE
musicdb10=>  insert into test05 values(1, 'Hello world!');
INSERT 0 1
musicdb10=>  select * from test05 ;   
 id |         comm         
----+----------------------
  1 | Hello world!        
(1 row)

select * from musicdb10.public.test05;
select * from omm.public.test05;
select * from postgres.public.test05;