openGauss每日一练第 4 天 | 一个数据库被多个用户访问

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

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。

课后作业
1.创建用户user1、user2、user3，授予user1、user2、user3数据库系统的SYSADMIN权限
root@modb:~# su - omm
omm@modb:~$ gsql -r

Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.

omm=# create user user1 identified by 'test@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# create user user2 identified by 'test@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# create user user3 identified by 'test@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# alter user user1 sysadmin;
ALTER ROLE
omm=# alter user user2 sysadmin;
ALTER ROLE
omm=# alter user user3 sysadmin;
ALTER ROLE
omm=# \du  查看有哪些用户

 user1     | Sysadmin                                                                                            
             | {}
 user2     | Sysadmin                                                                                            
             | {}
 user3     | Sysadmin                                                                                            
             | {}

                                                              List of roles
 Role name |                                                    Attributes                                       
             | Member of 
-----------+-----------------------------------------------------------------------------------------------------
-------------+-----------
 gaussdb   | Sysadmin                                                                                            
             | {}
 omm       | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policy
admin, UseFT | {}

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

字段名 数据类型 含义
product_id INTEGER 产品编号
product_name Char(20) 产品名
category Char(30) 种类

向表中插入数据：

product_id product_name category
1502 olympus camera electrncs
1601 lamaze toys
1700 wait interface Books
1666 harry potter toys

omm=# drop database if exists musicdb2;
NOTICE:  database "musicdb2" does not exist, skipping
DROP DATABASE
omm=# create tablespace music2_tbs relative location 'tablespace/test_ts2';
CREATE TABLESPACE
omm=# create database musicdb2 with tablespace=music2_tbs;
CREATE DATABASE

omm=# \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 products1(product_id int,product_name char(20),category char(30));
CREATE TABLE
musicdb2=> insert into products1 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb2=>** insert into products1 values(1601,'lamaze','toys');**
INSERT 0 1
musicdb2=> insert into products1 values(1700,'wait interface','Books');
INSERT 0 1
musicdb2=> insert into products1 values(1666,'harry potter','toys');
INSERT 0 1

musicdb2=> \c musicdb2 user2
Password for user user2: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb2" as user "user2".
musicdb2=> create table products2(product_id int,product_name char(20),category char(30));
CREATE TABLE
musicdb2=> insert into products2 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb2=> insert into products2 values(1601,'lamaze','toys');
INSERT 0 1
musicdb2=> insert into products2 values(1700,'wait interface','Books');
INSERT 0 1
musicdb2=> insert into products2 values(1666,'harry potter','toys');
musicdb2=> INSERT 0 1

musicdb2=> \c musicdb2 user3
Password for user user3: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb2" as user "user3".

musicdb2=> create table products3(product_id int,product_name char(20),category char(30));
CREATE TABLE
musicdb2=> insert into products3 values(1502,'olympus camera','electrncs');
INSERT 0 1
musicdb2=> insert into products3 values(1601,'lamaze','toys');
INSERT 0 1
musicdb2=> insert into products3 values(1700,'wait interface','Books');
INSERT 0 1
musicdb2=> insert into products3 values(1666,'harry potter','toys');
INSERT 0 1

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

musicdb2=> \dt

 Schema |   Name    | Type  | Owner |             Storage              
--------+-----------+-------+-------+----------------------------------
 public | products1 | table | user1 | {orientation=row,compression=no}
 public | products2 | table | user2 | {orientation=row,compression=no}
 public | products3 | table | user3 | {orientation=row,compression=no}
(3 rows)