域名預(yù)訂/競(jìng)價(jià)，好“米”不錯(cuò)過(guò)

在實(shí)際的生產(chǎn)環(huán)境 ，我們經(jīng)常會(huì)碰到這樣的情況：因?yàn)闃I(yè)務(wù)場(chǎng)景需要，本部門(mén)某些重要的業(yè)務(wù)數(shù)據(jù)表需要給予其他部門(mén)查看權(quán)限，因業(yè)務(wù)的擴(kuò)展及調(diào)整，后期可能需要放開(kāi)更多的表查詢(xún)權(quán)限。為解決此種業(yè)務(wù)需求，我們可以采用創(chuàng)建視圖的方式來(lái)解決，已可以通過(guò)創(chuàng)建影子用戶(hù)的方式來(lái)滿(mǎn)足需求，本文主要介紹影子用戶(hù)的創(chuàng)建及授權(quán)方法。

場(chǎng)景1：只授予usage on schema 權(quán)限

session 1:

--創(chuàng)建readonly用戶(hù)，并將test模式賦予readonly用戶(hù)。

postgres=# create user readonly with password 'postgres';
CREATE ROLE
postgres=# grant usage on schema test to readonly;
GRANT
postgres=# \dn
List of schemas
 Name | Owner
-------+-------
 test | postgres

session 2:

--登陸readonly用戶(hù)可以查詢(xún)test模式下現(xiàn)存的所有表。

postgres=# \c postgres readonly
You are now connected to database "postgres" as user "readonly".
postgres=> select * from test.emp ;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | WARD  | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | JONES | MANAGER  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | BLAKE | MANAGER  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | CLARK | MANAGER  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | KING  | PRESIDENT |   | 1981-11-17 | 5000.00 |     |   10
 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | JAMES | CLERK   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | FORD  | ANALYST  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | MILLER | CLERK   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | ANALYST  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | ADAMS | CLERK   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | SMITH | CLERK   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

換到session 1創(chuàng)建新表t1

postgres=# create table test.t1 as select * from test.emp;CREATE TABLE

切換到session 2 readonly用戶(hù)下，t1表無(wú)法查詢(xún)

postgres=> select * from test.t1 ;
2021-03-02 15:25:33.290 CST [21059] ERROR: permission denied for table t1
2021-03-02 15:25:33.290 CST [21059] STATEMENT: select * from test.t1 ;
**ERROR: permission denied for table t1

結(jié)論：如果只授予 usage on schema 權(quán)限，readonly 只能查看 test 模式下已經(jīng)存在的表和對(duì)象。在授予 usage on schema 權(quán)限之后創(chuàng)建的新表無(wú)法查看。

場(chǎng)景2：授予usage on schema 權(quán)限之后，再賦予 select on all tables in schema 權(quán)限

針對(duì)上個(gè)場(chǎng)景session 2 **ERROR: permission denied for table t1 錯(cuò)誤的處理

postgres=> select * from test.t1 ;**ERROR: permission denied for table t1

session 1： 使用postgres用戶(hù)授予readonly用戶(hù) select on all tables 權(quán)限

1postgres=# grant select on all tables in schema test TO readonly ;

session 2: readonly用戶(hù)查詢(xún) t1 表

postgres=> select * from test.t1;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | WARD  | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | JONES | MANAGER  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | BLAKE | MANAGER  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | CLARK | MANAGER  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | KING  | PRESIDENT |   | 1981-11-17 | 5000.00 |     |   10
 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | JAMES | CLERK   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | FORD  | ANALYST  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | MILLER | CLERK   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | ANALYST  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | ADAMS | CLERK   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | SMITH | CLERK   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

session1 ：postgres用戶(hù)的test模式下創(chuàng)建新表 t2

postgres=# create table test.t2 as select * from test.emp;SELECT 14

session 2：readonly用戶(hù)查詢(xún) t2 表權(quán)限不足

postgres=> select * from test.t2 ;ERROR: permission denied for table t2

session 1：再次賦予 grant select on all tables

1postgres=# grant select on all tables in schema test TO readonly ;

session 2：readonly用戶(hù)又可以查看 T2 表

postgres=> select * from test.t2 ;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | WARD  | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | JONES | MANAGER  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | BLAKE | MANAGER  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | CLARK | MANAGER  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | KING  | PRESIDENT |   | 1981-11-17 | 5000.00 |     |   10
 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | JAMES | CLERK   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | FORD  | ANALYST  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | MILLER | CLERK   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | ANALYST  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | ADAMS | CLERK   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | SMITH | CLERK   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

影子用戶(hù)創(chuàng)建

如果想讓readonly只讀用戶(hù)不在每次 postgres用戶(hù)在test模式中創(chuàng)建新表后都要手工賦予 grant select on all tables in schema test TO readonly 權(quán)限。則需要授予對(duì)test默認(rèn)的訪問(wèn)權(quán)限，對(duì)于test模式新創(chuàng)建的也生效。

session 1：未來(lái)訪問(wèn)test模式下所有新建的表賦權(quán)，創(chuàng)建 t5 表。

postgres=# alter default privileges in schema test grant select on tables to readonly ;
ALTER DEFAULT PRIVILEGES
postgres=# create table test.t5 as select * from test.emp;
CREATE TABLE

session 2：查詢(xún)r(jià)eadonly用戶(hù)

postgres=> select * from test.t5;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | WARD  | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | JONES | MANAGER  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | BLAKE | MANAGER  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | CLARK | MANAGER  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | KING  | PRESIDENT |   | 1981-11-17 | 5000.00 |     |   10
 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | JAMES | CLERK   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | FORD  | ANALYST  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | MILLER | CLERK   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | ANALYST  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | ADAMS | CLERK   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | SMITH | CLERK   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

總結(jié)：影子用戶(hù)創(chuàng)建的步驟

--創(chuàng)建影子用戶(hù)
create user readonly with password 'postgres';
--將schema中usage權(quán)限賦予給readonly用戶(hù),訪問(wèn)所有已存在的表
grant usage on schema test to readonly;
grant select on all tables in schema test to readonly;
--未來(lái)訪問(wèn)test模式下所有新建的表
alter default privileges in schema test grant select on tables to readonly ;

文章來(lái)源：腳本之家

來(lái)源地址：https://www.jb51.net/article/207011.htm

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