openGauss每日一练第5天 | openGauss中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。

1.测试环境准备：

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.
--进入数据库omm，创建表空间、测试数据库
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
omm=# DROP DATABASE

omm=# drop database if exists musicdb2;
NOTICE:  database "musicdb2" does not exist, skipping
DROP DATABASE
omm=# 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.
omm=# DROP TABLESPACE
omm=# create tablespace music_tbs relative location 'tablesapce/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
--执行下面的SQL语句，创建用户user1：
omm=# create user user1 identified by 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE--授予user1数据库系统的SYSADMIN权限：
omm=# alter user user1 sysadmin;
ALTER ROLE

2.使用数据库用户user1登录到数据库musicdb1，创建一个表t11，并插入一条数据：

--用户user1登录到数据库musicdb1，创建表t11，并插入、查看数据
omm=# \c musicdb1 user1
Password for user user1: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb1" as user "user1".
musicdb1=> create table t11(col1 char(20));
CREATE TABLE
musicdb1=> insert into t11 values('Hello opengauss! 11');
musicdb1=> INSERT 0 1
select * from t11;
         col1         
----------------------
 Hello opengauss! 11 
(1 row)

3.使用数据库用户user1登录到数据库musicdb2，创建一个表t21，并插入一条数据：

--用户user1登录到数据库musicdb2，创建表t21，并插入、查看数据
musicdb1=> \c musicdb2 user1
Password for user user1: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb2" as user "user1".
musicdb2=> create table t21(col1 char(20));
CREATE TABLE
musicdb2=> insert into t21 values('Hello opengauss! 22');
INSERT 0 1
musicdb2=> select * from t21;
         col1         
----------------------
musicdb2=>  Hello opengauss! 22 
(1 row)

4.使用数据库用户user1登录到数据库musicdb3，创建一个表t31，并插入一条数据：

–用户user1登录到数据库musicdb3，创建表t31，并插入、查看数据
musicdb2=> \c musicdb3 user1 
Password for user user1: 
musicdb3=> Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb3" as user "user1".

musicdb3=> create table t31(col1 char(20));
CREATE TABLE
musicdb3=> insert into t31 values('Hello opengauss! 33');
musicdb3=> INSERT 0 1

musicdb3=> select * from t31;
(1 row)

musicdb3=>          col1         
----------------------
 Hello opengauss! 33 

课程作业

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

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=# create tablespace music_tbs relative location 'tablespace/test_ts1';
CREATE TABLESPACE
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

2.用户user10访问数据库postgres，创建一个表并插入数据

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 tp(col_p char(20));
CREATE TABLE
openGauss=> insert into tp values ('Hello opengauss! p');
INSERT 0 1
openGauss=> select * from tp ;
(1 row)

openGauss=>         col_p         
----------------------
 Hello opengauss! p 

3.用户user10访问数据库omm，创建一个表并插入数据

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 tom(col_o char(20));
CREATE TABLE
omm=> insert into tom values ('Hello opengauss! o');
INSERT 0 1
omm=> select * from tom ;
        col_o         
----------------------
 Hello opengauss! o  
(1 row)

4.用户user10访问数据库musicdb10，创建一个表并插入数据

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 tmu(col_m char(20));
CREATE TABLE
musicdb10=> insert into tmu values ('Hello opengauss! m');
musicdb10=> INSERT 0 1

musicdb10=> select * from tmu ;
        col_m         
----------------------
 Hello opengauss! m  
(1 row)