openGauss每日一练第5天 | 学习心得体会

1.学习目标
学习openGauss体系结构，使用一个用户访问多个数据库

2.课程学习
数据库用户user1可以访问不同的数据库（musicdb1、musicdb2、musicdb3）。

实验中user1用户在数据库musicdb1中创建了表t11、在数据库musicdb2创建了表t21、在数据库musicdb3中创建了表t31，验证了这个结论。
2.1 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=# 
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
DROP DATABASE
omm=# drop DATABASE  IF EXISTS  musicdb2;
DROP DATABASE
omm=# NOTICE:  database "musicdb2" does not exist, skipping
drop DATABASE  IF EXISTS  musicdb3;
NOTICE:  database "musicdb3" does not exist, skipping
DROP DATABASE
omm=# drop tablespace IF EXISTS music_tbs;
NOTICE:  Tablespace "music_tbs" does not exist, skipping.
DROP TABLESPACE
omm=# omm=# 
CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb1  WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# CREATE DATABASE musicdb2  WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# CREATE DATABASE musicdb3  WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=# 
omm=# --执行下面的SQL语句，创建用户user1：
omm=# 
omm=#  CREATE USER user1 IDENTIFIED BY 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=#  
omm=# --授予user1数据库系统的SYSADMIN权限：
omm=# 
omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE

2.2 使用数据库用户user1,2,3登录到数据库musicdb1，2,3创建一个表t11，21,31并插入一条数据：

Password for user user1: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb1" as user "user1".
musicdb1=> create table t11(col1 char(20));
CREATE TABLE
musicdb1=>  insert into t11 values('Hello openGauss! 11');
musicdb1=> INSERT 0 1
 select * from t11;
musicdb1=>          col1         
----------------------
 Hello openGauss! 11 
(1 row)


musicdb1=> \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 t21(col1 char(20));
CREATE TABLE
musicdb2=>  insert into t21 values('Hello openGauss! 22');
INSERT 0 1
musicdb2=>  select * from t21;
         col1         
----------------------
 Hello openGauss! 22 
(1 row)

musicdb2=> \c musicdb3 user1
Password for user user1: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb3" as user "user1".
musicdb3=> create table t31(col1 char(20));
CREATE TABLE
musicdb3=>  insert into t31 values('Hello openGauss! 33');
INSERT 0 1
musicdb3=>  select * from t31;
         col1         
----------------------
 Hello openGauss! 33 
(1 row)