openGauss每日一练第5天 | 一个用户访问多个数据库

打卡第五天，心得体会

 一个用户访问多个数据库？ 在oracle12c之前的数据库里面，还真没有这种操作。

用户在openGauss数据库里面是属于全局用户。

可有同个用户登录不同的数据库。

课程作业

1.创建数据库musicdb10，创建用户user10，赋予sysadmin权限

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=# \l 
                         List of databases
   Name    | Owner | Encoding | Collate | Ctype | Access privileges 
-----------+-------+----------+---------+-------+-------------------
 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
(4 rows)

omm=# create database musicdb10;
CREATE DATABASE
omm=# create  user user10 identified by 'huawei@123';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# alter user user10 sysadmin;
ALTER ROLE
omm=# 

2.用户user10访问数据库postgres，创建一个表并插入数据

omm=# \c postgres user10
Password for user user10: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "postgres" as user "user10".
openGauss=> create table tt(col1 char(20));
CREATE TABLE
openGauss=> insert into tt values ('hello');
INSERT 0 1
openGauss=> select * from tt;
         col1         
----------------------
 hello               
(1 row)

openGauss=> 

3.用户user10访问数据库omm，创建一个表并插入数据

openGauss=> \c omm
Password for user user10: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "user10".
omm=> create table t2 (col1 char(20));
omm=> CREATE TABLE
  
omm=> insert into t2 values ('omm');
INSERT 0 1
omm=> select * from t2;
         col1         
----------------------
 omm                 
(1 row)

omm=> 

4.用户user10访问数据库musicdb10，创建一个表并插入数据

omm=> \c musicdb10
Password for user user10: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb10" as user "user10".
musicdb10=> create table t3 (col1 char(20));
CREATE TABLE
musicdb10=> insert into t3 values ('music');
INSERT 0 1
musicdb10=> select * from t3;
         col1         
----------------------
 music               
(1 row)

musicdb10=>