本节简单介绍了Oracle VPD。VPD用于实现精细化的权限管理。

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About Oracle Virtual Private Database

What?
VPD的做法：VPD自动添加where子句到SQL语句上
影响的对象：table、view、synonym
涉及的语句：select、insert、update、index和delete
不支持：DDL

基本做法示例：
SELECT FROM OE.ORDERS;
—>应用VPD
SELECT FROM OE.ORDERS
WHERE SALES_REP_ID = 159;

Benefits
Security：不管用户如何访问数据，都可以确保精细化的访问控制策略得到执行。
Simplicity：只需要在table、view上操作一次即可
Flexibility：select、insert、update、delete都可以有自己的策略

Using Oracle Virtual Private Database with an Application Context
SELECT FROM orders_tab
—>
SELECT FROM orders_tab
WHERE custno = SYS_CONTEXT (‘order_entry’, ‘cust_num’);

Components of an Oracle Virtual Private Database Policy

function
用于产生where子句（谓词）
输入参数：schema、object name
输出参数：where子句（有效的）

Configuring an Oracle Virtual Private Database Policy

What
function需与object进行绑定，可通过配置policy实现绑定。
policy本身用于管理VPD function，同时可以进行精细化访问控制，比如指定SQL语句类型或者策略影响的特定列。
Oracle提供了DBMS_RLS来进行策略管理：ADD、DROP、ENABLE/DISABLE…

How
例子：
SELECT fname, lname, ssn FROM emp;
—>
SELECT fname, lname, ssn FROM emp
WHERE ssn = ‘my_ssn’;

CREATE OR REPLACE FUNCTION hide_sal_comm (
v_schema IN VARCHAR2,
v_objname IN VARCHAR2)
RETURN VARCHAR2 AS
con VARCHAR2 (200);
BEGIN
con := ‘deptno=30’;
RETURN (con);
END hide_sal_comm;
/

BEGIN
DBMS_RLS.ADD_POLICY (
object_schema => ‘scott’,
object_name => ‘emp’,
policy_name => ‘hide_sal_policy’,
policy_function => ‘hide_sal_comm’,
sec_relevant_cols => ‘sal,comm’);
END;
/

— 设置敏感列输出
BEGIN
DBMS_RLS.ADD_POLICY(
object_schema => ‘scott’,
object_name => ‘emp’,
policy_name => ‘hide_sal_policy’,
policy_function => ‘hide_sal_comm’,
sec_relevant_cols =>’ sal,comm’,
sec_relevant_cols_opt => dbms_rls.ALL_ROWS);
END;
/

Tutorials

创建数据表，设定谓词为：username=’测试’

drop table t_vpd_1;
create table t_vpd_1(id int,username varchar2(20),name varchar2(30));
insert into t_vpd_1(id,username,name) values(1,'test','name1');
insert into t_vpd_1(id,username,name) values(2,'张三','name1');
insert into t_vpd_1(id,username,name) values(3,'测试','测试名称1');
insert into t_vpd_1(id,username,name) values(4,'测试','测试名称2');
commit;

创建函数

CREATE OR REPLACE FUNCTION func_testvpd_1( 
  schemaname IN VARCHAR2,
  tablename  IN VARCHAR2
 )
 RETURN VARCHAR2
 IS
  ret VARCHAR2 (400);
 BEGIN
  ret := 'username = ''测试''';
  RETURN ret;
 END func_testvpd_1;
/

创建策略(select)

BEGIN
  DBMS_RLS.DROP_POLICY (
    object_schema    => 'test',
    object_name      => 't_vpd_1',
    policy_name      => 'policy_t_vpd_1'
   );
 END;
/
BEGIN
  DBMS_RLS.ADD_POLICY (
    object_schema    => 'test',
    object_name      => 't_vpd_1',
    policy_name      => 'policy_t_vpd_1',
    function_schema  => 'test',
    policy_function  => 'func_testvpd_1',
    statement_types  => 'select'
   );
 END;
/

测试策略

-- 查询
select * from t_vpd_1;
-- 插入
TEST-orcl@DESKTOP-V430TU3>create table t_vpd_2 as select * from t_vpd_1 where 1=2;
Table created.
TEST-orcl@DESKTOP-V430TU3>insert into t_vpd_2(id,username,name) select * from t_vpd_1;
2 rows created.
TEST-orcl@DESKTOP-V430TU3>delete from t_vpd_1;
4 rows deleted.
TEST-orcl@DESKTOP-V430TU3>
TEST-orcl@DESKTOP-V430TU3>update t_vpd_1 set name = 'test';
0 rows updated.

创建策略(select、insert、update、delete)

BEGIN
  DBMS_RLS.DROP_POLICY (
    object_schema    => 'test',
    object_name      => 't_vpd_1',
    policy_name      => 'policy_t_vpd_1'
   );
 END;
/
BEGIN
  DBMS_RLS.ADD_POLICY (
    object_schema    => 'test',
    object_name      => 't_vpd_1',
    policy_name      => 'policy_t_vpd_1',
    function_schema  => 'test',
    policy_function  => 'func_testvpd_1',
    statement_types  => 'select,insert,update,delete'
   );
 END;
/

测试策略

insert into t_vpd_1(id,username,name) values(1,'test','name1');
insert into t_vpd_1(id,username,name) values(2,'张三','name1');
insert into t_vpd_1(id,username,name) values(3,'测试','测试名称1');
insert into t_vpd_1(id,username,name) values(4,'测试','测试名称2');
commit;
-- 查询
TEST-orcl@DESKTOP-V430TU3>select * from t_vpd_1;
        ID USERNAME             NAME
---------- -------------------- ------------------------------
         3 测试                 测试名称1
         4 测试                 测试名称2
-- 插入
TEST-orcl@DESKTOP-V430TU3>drop table t_vpd_2 ;
Table dropped.
TEST-orcl@DESKTOP-V430TU3>create table t_vpd_2 as select * from t_vpd_1 where 1=2;
Table created.
TEST-orcl@DESKTOP-V430TU3>insert into t_vpd_2(id,username,name) select * from t_vpd_1;
2 rows created.
TEST-orcl@DESKTOP-V430TU3>update t_vpd_1 set name = 'test';
2 rows updated.
TEST-orcl@DESKTOP-V430TU3>delete from t_vpd_1;
2 rows deleted.
TEST-orcl@DESKTOP-V430TU3>