为什么Oracle同义词会向基础表返回不同数量的行？

我有一个非常不寻常的情况,我希望有人能够阐明.我对oracle同义词的理解是它基本上是另一个模式中表的别名.

当我从同义词进行计数时,它返回零行.当我从基础表执行相同操作时,它返回12,000行.

我无法解释这种差异.有人可以帮忙吗？

select * from dba_synonyms
where synonym_name = 'CS_INCIDENTS_B_SEC';

OWNER  SYNONYM_NAME        TABLE_OWNER  TABLE_NAME          DB_LINK
------ ------------------- ------------ ------------------- -------
APPS   CS_INCIDENTS_B_SEC  CS           CS_INCIDENTS_ALL_B         



select count(*) from CS.CS_INCIDENTS_ALL_B;

COUNT(*)               
---------------------- 
12549                  

select count(*) from APPS.CS_INCIDENTS_B_SEC;

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

解释计划：

直接在桌子上……

EXPLAIN PLAN FOR
SELECT  *
FROM    CS.CS_INCIDENTS_ALL_B

PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------
| Id  | Operation         | Name               | Rows | Bytes| Cost(%CPU)|
--------------------------------------------------------------------------
|   0 | SELECT STATEMENT  |                    | 6056 | 1549K|  122   (3)|
|   1 |  TABLE ACCESS FULL| CS_INCIDENTS_ALL_B | 6056 | 1549K|  122   (3)|
--------------------------------------------------------------------------

通过同义词……

EXPLAIN PLAN FOR
SELECT  *
FROM    APPS.CS_INCIDENTS_B_SEC

PLAN_TABLE_OUTPUT
---------------------------------------------------------------------------
| Id  | Operation          | Name               | Rows | Bytes| Cost(%CPU)|
---------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |                    |    1 |  262 |    0   (0)|
|*  1 |  FILTER            |                    |      |      |           |
|   2 |   TABLE ACCESS FULL| CS_INCIDENTS_ALL_B | 6056 | 1549K|  122   (3)|
---------------------------------------------------------------------------

1 - filter(NULL IS NOT NULL)

同义词链……

SQL> SELECT  *
  2  FROM    dba_synonyms
  3  START WITH
  4          owner = 'CS'
  5          AND synonym_name = 'CS_INCIDENTS_ALL_B'
  6  CONNECT BY
  7          owner = PRIOR table_owner
  8          AND synonym_name = PRIOR table_name
  9  /

no rows selected

SQL> SELECT  *
  2  FROM    dba_synonyms
  3  START WITH
  4          owner = 'APPS'
  5          AND synonym_name = 'CS_INCIDENTS_B_SEC'
  6  CONNECT BY
  7          owner = PRIOR table_owner
  8          AND synonym_name = PRIOR table_name
  9  /

检查数据库的策略…

SQL> SELECT *
  2  FROM dba_policies
  3  WHERE OBJECT_NAME = 'CS_INCIDENTS_B_SEC'
  4  /

OBJECT_OWNER  OBJECT_NAME         POLICY_GROUP  POLICY_NAME          
------------- ------------------- ------------- -------------------- 
APPS          CS_INCIDENTS_B_SEC  SYS_DEFAULT   CS_SR_SEC_SR_ACCESS  


PF_OWNER  PACKAGE            FUNCTION       SEL INS UPD DEL IDX CHK 
--------- ------------------ -------------- --- --- --- --- --- --- 
APPS      FND_GENERIC_POLICY GET_PREDICATE  YES NO  NO  NO  NO  NO  


ENABLE STATIC_POLICY POLICY_TYPE  LONG_PREDICATE
------ ------------- ------------ --------------
YES    NO            DYNAMIC      YES

解决方法

更新：

您已启用ROW LEVEL SECURITY.

每次访问表时都会调用用户函数FND_GENERIC_POLICY.GET_PREDICATE,并限制对某些行的访问.

它会返回不同的结果,具体取决于您如何访问表：直接或通过SYNONYM.

您需要查看该函数并查看正在进行的操作(或在此处发布函数文本).