openGauss每日一练第4天 - 学习心得体会

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。

1.测试环境准备：

su - omm
gsql -r
--进入数据库omm，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;

CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE DATABASE musicdb  WITH TABLESPACE = music_tbs;

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';
 
--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;

--执行下面的命令，查看有哪些用户：
 \du

2.在终端中，分别使用user1、user2、user3用户访问数据库musicdb。

 --以用户user1的身份在数据库musicdb中创建表t1，并插入一条数据：
 \c musicdb user1
  
  create table t1(col1 char(20));
  insert into t1 values('Hello kunpeng 1');
  select * from t1;
 
--以用户user2的身份在数据库musicdb中创建表t2，并插入一条数据：
  \c musicdb user2

  create table t2(col1 char(20));
  insert into t2 values('Hello kunpeng 2');
  select * from t2;


--以用户user3的身份在数据库musicdb中创建表t3，并插入一条数据：
  \c musicdb user3

  create table t3(col1 char(20));
  insert into t3 values('Hello kunpeng 3');
  select * from t3;

3.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musicdb有哪些表：

 \dt                     

课后作业

准备:

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
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;
DROP TABLESPACE

1.创建用户user1、user2、user3，授予user1、user2、user3数据库系统的SYSADMIN权限

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
 

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

向表中插入数据：

omm=# \c musicdb user11
Password for user user11: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user11".
musicdb=> create table products1(product_id INT,product_name char(20),category char(30));
musicdb=> CREATE TABLE

musicdb=> insert into products1 values (1502,'olympus camera','category');
INSERT 0 1
musicdb=> insert into products1 values (1601,'lamaze','toys');
INSERT 0 1
musicdb=> insert into products1 values (1700,'wait interface','Books');
musicdb=> INSERT 0 1

musicdb=> insert into products1 values (1666,'harry potter','toys');
INSERT 0 1

musicdb=> select * from products1;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | category                      
       1601 | lamaze               | toys                          
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(4 rows)

musicdb=> \c musicdb user22
Password for user user22: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user22".
musicdb=> create table products1(product_id INT,product_name char(20),category char(30));
ERROR:  relation "products1" already exists in schema "public"
DETAIL:  creating new table with existing name in the same schema
musicdb=> create table products2(product_id INT,product_name char(20),category char(30));
CREATE TABLE
musicdb=> insert into products2 values (1502,'olympus camera','category');
INSERT 0 1
musicdb=> insert into products2 values (1601,'lamaze','toys');
INSERT 0 1
musicdb=> insert into products2 values (1700,'wait interface','Books');
INSERT 0 1
musicdb=> insert into products2 values (1666,'harry potter','toys');
INSERT 0 1
musicdb=> select * from products2;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | category                      
       1601 | lamaze               | toys                          
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(4 rows)

musicdb=> \c musicdb user33
Password for user user33: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user33".
musicdb=> create table products3(product_id INT,product_name char(20),category char(30));
CREATE TABLE
musicdb=> insert into products3 values (1502,'olympus camera','category');
INSERT 0 1
musicdb=> insert into products3 values (1601,'lamaze','toys');
INSERT 0 1
musicdb=> insert into products3 values (1700,'wait interface','Books');
INSERT 0 1
musicdb=> insert into products3 values (1666,'harry potter','toys');
musicdb=> INSERT 0 1

musicdb=> select * from products3;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | category                      
       1601 | lamaze               | toys                          
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(4 rows)

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

musicdb=> \c musicdb user11
Password for user user11: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb" as user "user11".
musicdb=> \dt 
                           List of relations
 Schema |   Name    | Type  | Owner  |             Storage              
--------+-----------+-------+--------+----------------------------------
 public | products1 | table | user11 | {orientation=row,compression=no}
 public | products2 | table | user22 | {orientation=row,compression=no}
 public | products3 | table | user33 | {orientation=row,compression=no}
 public | t1        | table | user1  | {orientation=row,compression=no}
 public | t2        | table | user2  | {orientation=row,compression=no}
 public | t3        | table | user3  | {orientation=row,compression=no}
(6 rows)