先把用户切一下

root@modb:~# su - omm
omm@modb:~$ gsql -r

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作业

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

omm=# CREATE TABLESPACE music_tbs10 RELATIVE LOCATION 'tablespace/ts10';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb10  WITH TABLESPACE = music_tbs10;
CREATE DATABASE
omm=# 
omm=# CREATE USER user10 IDENTIFIED BY '1111@aaaa';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
omm=# ALTER USER user10 SYSADMIN;
ALTER ROLE
omm=# 
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2.用户user10访问数据库postgres，创建一个表并插入数据

3.用户user10访问数据库omm，创建一个表并插入数据

4.用户user10访问数据库musicdb10，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 table1 (id int);
CREATE TABLE
openGauss=> insert into table1 values(1);
INSERT 0 1
openGauss=> \c omm user10
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 table1 (id int);
CREATE TABLE
omm=> insert into table1 values(1);
INSERT 0 1

omm-> \c musicdb10 user10
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 table1 (id int);
CREATE TABLE
musicdb10=> insert into table1 values(1);
INSERT 0 1
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扩展–数据库授权

默认所有用户可以访问所有的数据库，可以通过回收public的connect 权限，阻止未授权的访问，database owner不受影响，sysdba不受影响

omm=# create user user20 identified by '1111@aaaa';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE

omm=# \c musicdb10 user20
Password for user user20: 
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "musicdb10" as user "user20".

musicdb10=> \c omm omm;
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "omm".
omm=# revoke connect on database musicdb10 from  public;
REVOKE
omm=# \c musicdb10 user20
Password for user user20: 
FATAL:  permission denied for database "musicdb10"
DETAIL:  User does not have CONNECT privilege.
Previous connection kept
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