openGauss每日一练第4天 | 学习心得体会

1.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

2.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。

3.实验测试
3.1测试环境准备

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=# --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
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;
DROP TABLESPACE
omm=# 
NOTICE:  Tablespace "music_tbs" does not exist, skipping.
omm=# CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb  WITH TABLESPACE = music_tbs;
CREATE DATABASE

3.2 创建用户user1、user2、user3
``` 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
omm=#
omm=# --授予user1、user2、user3数据库系统的SYSADMIN权限：
omm=#
omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user2 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user3 SYSADMIN;
ALTER ROLE
omm=#
omm=# --执行下面的命令，查看有哪些用户：
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 | {}
user2 | Sysadmin | {}
user3 | Sysadmin

                  

 4. 在终端中，分别使用user1、user2、user3用户访问数据库musicdb
  ```  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=> create table t1(col1 char(20));
CREATE TABLE
musicdb=>   insert into t1 values('Hello kunpeng 1');
musicdb=>   select * from t1;INSERT 0 1

         col1         
----------------------
 Hello kunpeng 1     
(1 row)

musicdb=> create table t2(col1 char(20));
CREATE TABLE
musicdb=>   insert into t2 values('Hello kunpeng 2');
INSERT 0 1

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