前言：
最近参加了由opengauss、墨天轮、鲲鹏社区一起推出的活动《每日一练 opengauss 3.0.0 数据库在线实训课程》，共21天，墨天轮提供实操环境，特此记录学习笔记。
活动详情：https://www.modb.pro/db/551619
主题：
学习openGauss体系结构，体会多个用户访问同一个数据库
学习笔记：
在一个openGauss DBMS上，一个数据库可以被多个用户访问。
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。
1.进入测试环境：建立数据库
–进入数据库，当然还是需要使用:su - omm
su - omm
gsql -r
查看数据库表空间及文件信息：
\db
\l
|
omm=# \db
List of tablespaces
Name | Owner | Location
------------±------±--------------------
music_tbs | omm | tablespace/test_ts1
pg_default | omm |
pg_global | omm |
(3 rows)
omm=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------±------±---------±--------±------±------------------
musicdb | omm | UTF8 | C | C |
musicdb1 | 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
(8 rows)
omm=#
|
发现昨天建的数据库表空间及文件都还存在，为了巩固学习成果，把表空间删除，然后再建立
–删除同名数据库及表空间，然后创建表空间、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;
|
omm=# drop DATABASE IF EXISTS musicdb;
DROP DATABASE
omm=# drop DATABASE IF EXISTS musicdb1;
DROP DATABASE
omm=# drop DATABASE IF EXISTS musicdb2;
DROP DATABASE
omm=# drop DATABASE IF EXISTS musicdb3;
DROP DATABASE
omm=# drop TABLESPACE IF EXISTS music_tbs;
DROP TABLESPACE
omm=#
|
CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE DATABASE musicdb2 WITH TABLESPACE = music_tbs;
|
omm=# CREATE TABLESPACE music_tbs RELATIVE LOCATION ‘tablespace/test_ts1’;
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb2 WITH TABLESPACE =music_tbs;
CREATE DATABASE
omm=#
|
2.创建用户user1、user2、user3
–执行下面的SQL语句，创建用户user1、user2、user3：
CREATE USER user1 IDENTIFIED BY 'kunpeng@1234';
CREATE USER user2 IDENTIFIED BY 'kunpeng@1234';
CREATE USER user3 IDENTIFIED BY 'kunpeng@1234';
|
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=#
|
–授予user1、user2、user3数据库系统的SYSADMIN权限：
ALTER USER user1 SYSADMIN;
ALTER USER user2 SYSADMIN;
ALTER USER user3 SYSADMIN;
|
omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user2 SYSADMIN;
ALTER ROLE
omm=# ALTER USER user3 SYSADMIN;
ALTER ROLE
omm=#
|
–执行下面的命令，查看有哪些用户：
\du
|
omm=# \du
List of rol
es
Role name | Attribute
s | Member of
-----------±------------------------------------------------------------
-----------------------------------------------------±----------
gaussdb | Sysadmin
| {}
omm | Sysadmin, Create role, Create DB, Replication, Administer au
dit, Monitoradmin, Operatoradmin, Policyadmin, UseFT | {}
user1 | Sysadmin
| {}
user2 | Sysadmin
| {}
user3 | Sysadmin
| {}
omm=#
|
已经看到有3个用户user1、user2和user3了
3.在终端中，分别使用user1、user2、user3用户访问数据库musicdb2并分别插入数据。
–以用户user1的身份在数据库musicdb2中创建表t1，并插入一条数据：
\c musicdb2 user1
create table t1(product_id INTEGER,product_name Char(20),category Char(30));
insert into t1 values(1502,'olympus camera','electrncs');
insert into t1 values(1601,'lamaze','toys');
select * from t1;
|
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 t1(product_id INTEGER,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=> select * from products1;
product_id | product_name | category
------------±---------------------±-------------------------------
1502 | olympus camera | electrncs
1601 | lamaze | toys
(2 rows)
musicdb2=>
|
–以用户user2的身份在数据库musicdb2中创建表t2，并插入一条数据：
\c musicdb2 user2
create table t2(product_id INTEGER,product_name Char(20),category Char(30));
insert into t2 values(1700,'wait interface','Books');
insert into t2 values(1666,'harry potter','toys');
select * from t2;
|
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 t2(product_id INTEGER,product_name Char(20),category Char(30));
CREATE TABLE
musicdb2=> insert into t2 values(1700,‘wait interface’,‘Books’);
INSERT 0 1
musicdb2=> insert into t2 values(1666,‘harry potter’,‘toys’);
INSERT 0 1
musicdb2=> select * from t2;
product_id | product_name | category
------------±---------------------±-------------------------------
1700 | wait interface | Books
1666 | harry potter | toys
(2 rows)
musicdb2=>
|
–以用户user3的身份在数据库musicdb2中创建表t3，并插入一条数据：
\c musicdb2 user3
create table t3(product_id INTEGER,product_name Char(20),category Char(30));
insert into t3 values(1502,'olympus camera','electrncs');
insert into t3 values(1601,'lamaze','toys');
insert into t3 values(1700,'wait interface','Books');
insert into t3 values(1666,'harry potter','toys');
select * from t3;
|
musicdb=> \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”.
musicdb=> create table t3(product_id INTEGER,product_name Char(20),category Char(30));
CREATE TABLE
musicdb2=> insert into t3 values(1502,‘olympus camera’,‘electrncs’);
INSERT 0 1
musicdb2=> insert into t3 values(1601,‘lamaze’,‘toys’);
INSERT 0 1
musicdb2=> insert into t3 values(1700,‘wait interface’,‘Books’);
INSERT 0 1
musicdb2=> insert into t3 values(1666,‘harry potter’,‘toys’);
INSERT 0 1
musicdb2=> select * from t3;
product_id | product_name | category
------------±---------------------±-------------------------------
1502 | olympus camera | electrncs
1601 | lamaze | toys
1700 | wait interface | Books
1666 | harry potter | toys
(4 rows)
musicdb2=>
|
4.使用user1、user2、user3用户中的任何一个，执行如下命令，查看当前数据库musicdb2有哪些表：
\dt
|
musicdb2=> \dt
List of relations
Schema | Name | Type | Owner | Storage
--------±----------±------±------±---------------------------------
public | t1 | table | user1 | {orientation=row,compression=no}
public | t2 | table | user2 | {orientation=row,compression=no}
public | t3 | table | user3 | {orientation=row,compression=no}
(3 rows)
musicdb2=>
|
总结
通过第四天的学习中，我们学到了一个数据库可以被多个有权限的用户进行连接与管理。知道了openGauss数据库中数据库和用户的关系。同时在学习的过程中不断的提升自己的技能。
