postgres 基于Schema 权限访问探讨

01，环境配置

　　　创建用户，和schema

postgres=# create user test1 with password 'test1';
CREATE ROLE
postgres=# create user test2 with password 'test2';
CREATE ROLE
postgres=# create schema u1;
CREATE SCHEMA
postgres=# create schema u2;
CREATE SCHEMA
postgres=# insert into u1.txt1 values (1,'hello')
;
INSERT 0 1
postgres=# insert into u1.txt2 values (2,'world')
;
INSERT 0 1
postgres=# insert into u2.txt1 values (1,'hello')
;
INSERT 0 1
postgres=# insert into u2.txt2 values (2,'world')
;
INSERT 0 1



创建环境

02，权限访问

postgres=# select current_user  -- 查看当前的schema
postgres-# ; 
 current_user
--------------
 postgres
(1 row)

postgres=# show search_path -- 看到当前是public schema
postgres-# ;
   search_path
-----------------
 "$user", public
(1 row)

postgres=# \dt              -- 查看当前的表，发现并没有刚刚创建的表
        List of relations
 Schema | Name | Type  |  Owner
--------+------+-------+----------
 public | test | table | postgres

postgres=# \c postgres test1 ;    --登入到 test1 用户
You are now connected to database "postgres" as user "test1".
postgres=> select current_user;   ---查看当前用户
 current_user
--------------
 test1
(1 row)

postgres=> \dt;                 -- 发现当前只能读取public的表
        List of relations
 Schema | Name | Type  |  Owner
--------+------+-------+----------
 public | test | table | postgres
(1 row)

postgres=> show search_path ;  ---看当前schema
   search_path
-----------------
 "$user", public
(1 row)
postgres=> set search_path = 'u1';   ---切换到u1
SET
postgres=> show search_path ;   -查看
 search_path
-------------
 u1
(1 row)

postgres=> \dt;        --发现并没有 表出来，我不是创建的时候指定了吗？
Did not find any relations.



postgres=> set search_path = 'u1';
SET
postgres=> show search_path ;
 search_path
-------------
 u1
(1 row)

postgres=> \dt;
Did not find any relations.
postgres=> select * from u1.test1;  --- 查询，没有权限
ERROR:  permission denied for schema u1
LINE 1: select * from u1.test1;

我们通过 postgres 用户来看下

postgres=> \c postgres postgres
You are now connected to database "postgres" as user "postgres".
postgres=# show search_path
postgres-# ;
   search_path
-----------------
 "$user", public
(1 row)

postgres=# \d+
                   List of relations
 Schema | Name | Type  |  Owner   | Size  | Description
--------+------+-------+----------+-------+-------------
 public | test | table | postgres | 16 kB |
(1 row)

postgres=# set search_path = u1;
SET
postgres=# \d+
                      List of relations
 Schema | Name | Type  |  Owner   |    Size    | Description
--------+------+-------+----------+------------+-------------
 u1     | txt1 | table | postgres | 8192 bytes |
 u1     | txt2 | table | postgres | 8192 bytes |

发现是没有问题的。是不是权限不够呢？

那我授权下

postgres=# grant SELECT on u1.txt1 to test1 ;
GRANT
postgres=# \c postgres test1;
You are now connected to database "postgres" as user "test1".
postgres=> \d+
                   List of relations
 Schema | Name | Type  |  Owner   | Size  | Description
--------+------+-------+----------+-------+-------------
 public | test | table | postgres | 16 kB |
(1 row)

postgres=> set search_path = u1;
SET
postgres=> \d+
Did not find any relations.
postgres=> select * from u1.txt1 ;
ERROR:  permission denied for schema u1
LINE 1: select * from u1.txt1 ;
                      ^

发现还是权限不够

这时候其实是少了一个权限

postgres=# grant USAGE on SCHEMA u1 to test1 ;
GRANT
postgres=# \c postgres test1 ;
You are now connected to database "postgres" as user "test1".
postgres=> \dt ;
        List of relations
 Schema | Name | Type  |  Owner
--------+------+-------+----------
 public | test | table | postgres
(1 row)

postgres=> set search_path = u1 ;
SET
postgres=> \dt ;
        List of relations
 Schema | Name | Type  |  Owner
--------+------+-------+----------
 u1     | txt1 | table | postgres
 u1     | txt2 | table | postgres

postgres=> select * from txt1
postgres-> ;
 id | name
----+-------
  1 | hello
  1 | hello
(2 rows)

这样设置就可以了

　　　　所以一般使用schema 的时候注意：

　　　　　　　1　需要用postgres 授权指定的schema 的使用（USAGE）权限给特定用户

　　　　　　　2　然后授权postgres 需要的权限到特定用户

　　缺一不可