在oracle中更改或刪除重新創建表會影響在其上定義的策略

Question

如果我有一個表和定義的策略，那麼是否需要重新定義策略，如果我刪除並重新創建表或更改它，提供表格的改變或重新創建不會改變函數需要看到的元素？

Answer 1

"do I need to redefine the policy if I drop and recreate the table"

是的。我們來創建一個策略。

SQL> exec dbms_rls.add_policy('APC', 'T23', 'DEPTPOL', 'APC', 'security_policies.get_deptno_predicate') 

PL/SQL procedure successfully completed. 

SQL> select count(*) from user_policies; 

    COUNT(*) 
---------- 
     1 

SQL> exec security_policies.set_deptno(20) 

PL/SQL procedure successfully completed. 

SQL> select count(*) from t23; 

    COUNT(*) 
---------- 
     6 

SQL> 

這樣工作。但是，如果我們刪除並重新創建表（使用備份我提前準備好了）...變更表不降

SQL> drop table t23 
    2/

Table dropped. 

SQL> create table t23 as select * from t23a 
    2/

Table created. 

SQL> select count(*) from t23; 

    COUNT(*) 
---------- 
     11 

SQL> exec security_policies.set_deptno(20) 

PL/SQL procedure successfully completed. 

SQL> select count(*) from t23; 

    COUNT(*) 
---------- 
     11 

SQL> SQL> select count(*) from user_policies; 

    COUNT(*) 
---------- 
     0 

SQL> 

"So the question is if I must redefine the policy even if I will not change anything in the definition."

號提供的變化並不能否定生成的謂詞策略：

SQL> exec dbms_rls.add_policy('APC', 'T23', 'DEPTPOL', 'APC', 'security_policies.get_deptno_predicate') 

PL/SQL procedure successfully completed. 

SQL> alter table t23 modify deptno number(3,0) 
    2 
SQL> desc t23 
Name          Null? Type 
----------------------------------------- -------- ---------------------------- 
NAME            VARCHAR2(12 CHAR) 
ID             NUMBER 
AGE            NUMBER(4) 
DEPTNO            NUMBER(2) 

SQL> alter table t23 modify deptno number(3,0) 
    2/

Table altered. 

SQL> exec security_policies.set_deptno(20) 

PL/SQL procedure successfully completed. 

SQL> select count(*) from t23; 

    COUNT(*) 
---------- 
     6 

SQL> 

請注意，更改修改了由謂詞測試的列，並且策略仍然有效。

---

"does a 'CREATE OR REPLACE VIEW' statement drops and recreates it or does it alter it?"

讓我們試一下：

SQL> create view v23 as select * from t23; 

View created. 

SQL> exec dbms_rls.add_policy('APC', 'V23', 'DEPTPOLV', 'APC', 'security_policies.get_deptno_predicate') 

PL/SQL procedure successfully completed. 

SQL> exec security_policies.set_deptno(10) 

PL/SQL procedure successfully completed. 

SQL> select count(*) from v23; 

    COUNT(*) 
---------- 
     5 

SQL> create or replace view v23 as select name, age from t23; 

View created. 

SQL> select count(*) from v23; 
select count(*) from v23 
        * 
ERROR at line 1: 
ORA-28113: policy predicate has error 


SQL> 

好了，所以這是一個錯誤，因爲該視圖的新的投影不包括在謂詞列。但是它表明，這種方法仍然存在。所以我們來修正這個錯誤：

SQL> create or replace view v23 as select name, age, deptno from t23; 

View created. 

SQL> select count(*) from v23; 

    COUNT(*) 
---------- 
     5 

SQL>