PostgreSQL用户角色及其属性介绍

1.CREATE ROLE创建的用户默认不带LOGIN属性，而CREATE USER创建的用户默认带有LOGIN属性，如下：

postgres=# CREATE ROLE pg_test_user_1; /*默认不带LOGIN属性*/  
CREATE ROLE  
postgres=# CREATE USER pg_test_user_2; /*默认具有LOGIN属性*/  
CREATE ROLE  
postgres=# du  
               List of roles  
   Role name    |  Attributes  | Member of  
----------------+--------------+-----------  
 pg_test_user_1 | Cannot login | {}  
 pg_test_user_2 |              | {}  
 postgres       | Superuser    | {}  
                : Create role  
                : Create DB  
  
postgres=#

2.在创建用户时赋予角色属性

postgres=# CREATE  ROLE pg_test_user_3 CREATEDB;   /*具有创建数据库的属性*/  
CREATE ROLE  
postgres=# du  
               List of roles  
   Role name    |  Attributes  | Member of  
----------------+--------------+-----------  
 pg_test_user_1 | Cannot login | {}  
 pg_test_user_2 |              | {}  
 pg_test_user_3 | Create DB    | {}  
                : Cannot login  
 postgres       | Superuser    | {}  
                : Create role  
                : Create DB  
  
postgres=# CREATE ROLE pg_test_user_4 CREATEDB PASSWORD '123456'; /*具有创建数据库及带有密码登陆的属性 */    
CREATE ROLE  
postgres=# du  
               List of roles  
   Role name    |  Attributes  | Member of  
----------------+--------------+-----------  
 pg_test_user_1 | Cannot login | {}  
 pg_test_user_2 |              | {}  
 pg_test_user_3 | Create DB    | {}  
                : Cannot login  
 pg_test_user_4 | Create DB    | {}  
                : Cannot login  
 postgres       | Superuser    | {}  
                : Create role  
                : Create DB  
  
postgres=#

3.给已存在用户赋予各种权限

使用ALTER ROLE即可。

postgres=# du  
               List of roles  
   Role name    |  Attributes  | Member of  
----------------+--------------+-----------  
 pg_test_user_3 | Create DB    | {}  
                : Cannot login  
 pg_test_user_4 | Create DB    | {}  
                : Cannot login  
 postgres       | Superuser    | {}  
                : Create role  
                : Create DB  
  
postgres=# ALTER ROLE pg_test_user_3 WITH LOGIN; /*赋予登录权限*/  
ALTER ROLE  
postgres=# du  
               List of roles  
   Role name    |  Attributes  | Member of  
----------------+--------------+-----------  
 pg_test_user_3 | Create DB    | {}  
 pg_test_user_4 | Create DB    | {}  
                : Cannot login  
 postgres       | Superuser    | {}  
                : Create role  
                : Create DB  
  
postgres=# ALTER ROLE pg_test_user_4 WITH CREATEROLE;/*赋予创建角色的权限*/  
ALTER ROLE  
postgres=# du  
               List of roles  
   Role name    |  Attributes  | Member of  
----------------+--------------+-----------  
 pg_test_user_3 | Create DB    | {}  
 pg_test_user_4 | Create role  | {}  
                : Create DB  
                : Cannot login  
 postgres       | Superuser    | {}  
                : Create role  
                : Create DB  
  
postgres=# ALTER ROLE pg_test_user_4 WITH PASSWORD '654321';/*修改密码*/  
ALTER ROLE  
postgres=# ALTER ROLE pg_test_user_4 VALID UNTIL 'JUL 7 14:00:00 2012 +8'; /*设置角色的有效期*  
ALTER ROLE

4.查看角色表中的信息:

postgres=# SELECT * FROM pg_roles;  
    rolname     | rolsuper | rolinherit | rolcreaterole | rolcreatedb | rolcatupdate | rolcanlogin | rolconnlimit | rolpassword |     rolvaliduntil      | rol  
config |  oid  
----------------+----------+------------+---------------+-------------+--------------+-------------+--------------+-------------+------------------------+----  
-------+-------  
 postgres       | t        | t          | t             | t           | t            | t           |           -1 | ********    |                        |  
       |    10  
 pg_test_user_3 | f        | t          | f             | t           | f            | t           |           -1 | ********    |                        |  
       | 16390  
 pg_test_user_4 | f        | t          | t             | t           | f            | f           |           -1 | ********    | 2012-07-07 14:00:00+08 |  
       | 16391  
(3 rows)  
  
postgres=#

5.ALTER ROLE语句简介：

ALTER ROLE  
名称  
ALTER ROLE -- 修改一个数据库角色  
语法  
ALTER ROLE name [ [ WITH ] option [ ... ] ]  
  
这里的 option 可以是：  
      
      SUPERUSER | NOSUPERUSER  
    | CREATEDB | NOCREATEDB  
    | CREATEROLE | NOCREATEROLE  
    | CREATEUSER | NOCREATEUSER  
    | INHERIT | NOINHERIT  
    | LOGIN | NOLOGIN  
    | CONNECTION LIMIT connlimit  
    | [ ENCRYPTED | UNENCRYPTED ] PASSWORD 'password'  
    | VALID UNTIL 'timestamp'   
  
ALTER ROLE name RENAME TO newname  
  
ALTER ROLE name SET configuration_parameter { TO | = } { value | DEFAULT }  
ALTER ROLE name RESET configuration_parameter描述  
ALTER ROLE 修改一个数据库角色的属性。