openGauss每日一练第4天 | openGauss中一个数据库可以被多个用户访问

openGauss中一个数据库可以被多个用户访问，一个用户可以访问多个数据库。

1、创建用户和用户对应的表空间，并给用户授权

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.

--创建表空间
omm=# create tablespace music_tbs relative location 'tablespace/test_ts1';
omm=# CREATE TABLESPACE

创建数据库，并指定数据库表空间
omm=# create database musicdb2 with tablespace=music_tbs;  
CREATE DATABASE


--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

--授权user1、user2、user3 用户sysadmin角色权限
omm=# alter user user1 sysadmin;
ALTER ROLE
omm=# alter user user2 sysadmin;
ALTER ROLE
omm=# alter user user3 sysadmin;
ALTER ROLE

2、使用user1、user2、user3分别创建各自的表

--切换使用user1登录musicdb2数据库，来创建表和插入数据
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".

--查看当前数据库、当前用户、当前模式
musicdb2=> select current_database(),current_user,current_schema;
musicdb2=>  current_database | current_user | current_schema 
------------------+--------------+----------------
 musicdb2         | user1        | public
(1 row)

musicdb2=> create table products1(product_id int,product_name char(20),category char(30));
CREATE TABLE

                                                               
musicdb2=> insert into products1(product_id,product_name,category) values(1502,'olyera','electrncs'),(1601,'lamaze','toys'),(1700,'wait interface','Books'),(1666,'harr','toys');
INSERT 0 4


musicdb2=> select * from products1;
 product_id |     product_name     |            category            
------------+----------------------+--------------------------------
       1502 | olympus camera       | electrncs                     
       1601 | lamaze               | toys                          
       1700 | wait interface       | Books                         
       1666 | harry potter         | toys                          
(4 rows)

--切换使用user2登录musicdb2数据库，来创建表和插入数据
omm=# \c - user2
musicdb2=> create table products2(product_id int,product_name char(20),category char(30));
CREATE TABLE


musicdb2=> insert into products2(product_id,product_name,category) values(1502,'olyera','electrncs'),(1601,'lamaze','toys'),(1700,'wait interface','Books'),(1666,'harr','toys');
INSERT 0 4


--切换使用user3登录musicdb2数据库，来创建表和插入数据
omm=# \c - user3
musicdb2=> create table products3(product_id int,product_name char(20),category char(30));
CREATE TABLE


musicdb2=> insert into products3(product_id,product_name,category) values(1502,'olyera','electrncs'),(1601,'lamaze','toys'),(1700,'wait interface','Books'),(1666,'harr','toys');
INSERT 0 4

3、使用user1、user2、user3其中一个登录数据库，查看数据库下有哪些表

--查看当前数据库、当前用户、当前模式
musicdb2=>  select current_database(),current_user,current_schema;
 current_database | current_user | current_schema 
------------------+--------------+----------------
 musicdb2         | user3        | public
(1 row)


--查看当前数据库下有哪些表，可以看到3个表，owner分别属于user1、user2、user3用户
musicdb2=> \dt
                           List of relations
 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)

musicdb2=>