首先，我认为对付“流氓管理员”的方法是结合Oracle的审计追踪 and 数据库库特征。
也就是说，我可能会尝试以下方法：
1) 创建自定义 ODCI 聚合函数来计算多行的哈希作为聚合。
2）创建一个VIRTUAL NOT NULL表中的列是表中所有列的 SHA 哈希值，或者是您关心保护的所有列。你会一直保留这个——基本上是交换一些insert/update/delete性能以换取能够更快地计算哈希值。
3) 在该虚拟列上创建非唯一索引
4）SELECT my_aggregate_hash_function(virtual_hash_column) FROM my_table得到结果。
这是代码：
创建一个聚合函数来计算一堆行的 SHA 哈希值
CREATE OR REPLACE TYPE matt_hash_aggregate_impl AS OBJECT
(
hash_value RAW(32000),
CONSTRUCTOR FUNCTION matt_hash_aggregate_impl(SELF IN OUT NOCOPY matt_hash_aggregate_impl ) RETURN SELF AS RESULT,
-- Called to initialize a new aggregation context
-- For analytic functions, the aggregation context of the *previous* window is passed in, so we only need to adjust as needed instead
-- of creating the new aggregation context from scratch
STATIC FUNCTION ODCIAggregateInitialize (sctx IN OUT matt_hash_aggregate_impl) RETURN NUMBER,
-- Called when a new data point is added to an aggregation context
MEMBER FUNCTION ODCIAggregateIterate (self IN OUT matt_hash_aggregate_impl, value IN raw ) RETURN NUMBER,
-- Called to return the computed aggragate from an aggregation context
MEMBER FUNCTION ODCIAggregateTerminate (self IN matt_hash_aggregate_impl, returnValue OUT raw, flags IN NUMBER) RETURN NUMBER,
-- Called to merge to two aggregation contexts into one (e.g., merging results of parallel slaves)
MEMBER FUNCTION ODCIAggregateMerge (self IN OUT matt_hash_aggregate_impl, ctx2 IN matt_hash_aggregate_impl) RETURN NUMBER,
-- ODCIAggregateDelete
MEMBER FUNCTION ODCIAggregateDelete(self IN OUT matt_hash_aggregate_impl, value raw) RETURN NUMBER
);
/
CREATE OR REPLACE TYPE BODY matt_hash_aggregate_impl IS
CONSTRUCTOR FUNCTION matt_hash_aggregate_impl(SELF IN OUT NOCOPY matt_hash_aggregate_impl ) RETURN SELF AS RESULT IS
BEGIN
SELF.hash_value := null;
RETURN;
END;
STATIC FUNCTION ODCIAggregateInitialize (sctx IN OUT matt_hash_aggregate_impl) RETURN NUMBER IS
BEGIN
sctx := matt_hash_aggregate_impl ();
RETURN ODCIConst.Success;
END;
MEMBER FUNCTION ODCIAggregateIterate (self IN OUT matt_hash_aggregate_impl, value IN raw ) RETURN NUMBER IS
BEGIN
IF self.hash_value IS NULL THEN
self.hash_value := dbms_crypto.hash(value, dbms_crypto.hash_sh1);
ELSE
self.hash_value := dbms_crypto.hash(self.hash_value || value, dbms_crypto.hash_sh1);
END IF;
RETURN ODCIConst.Success;
END;
MEMBER FUNCTION ODCIAggregateTerminate (self IN matt_hash_aggregate_impl, returnValue OUT raw, flags IN NUMBER) RETURN NUMBER IS
BEGIN
returnValue := dbms_crypto.hash(self.hash_value,dbms_crypto.hash_sh1);
RETURN ODCIConst.Success;
END;
MEMBER FUNCTION ODCIAggregateMerge (self IN OUT matt_hash_aggregate_impl, ctx2 IN matt_hash_aggregate_impl) RETURN NUMBER IS
BEGIN
self.hash_value := dbms_crypto.hash(self.hash_value || ctx2.hash_value, dbms_crypto.hash_sh1);
RETURN ODCIConst.Success;
END;
-- ODCIAggregateDelete
MEMBER FUNCTION ODCIAggregateDelete(self IN OUT matt_hash_aggregate_impl, value raw) RETURN NUMBER IS
BEGIN
raise_application_error(-20001, 'Invalid operation -- hash aggregate function does not support windowing!');
END;
END;
/
CREATE OR REPLACE FUNCTION matt_hash_aggregate ( input raw) RETURN raw
PARALLEL_ENABLE AGGREGATE USING matt_hash_aggregate_impl;
/
创建一个要使用的测试表（您可以跳过此操作，因为您拥有真实的表）
create table mattmsi as select * from mtl_system_items where rownum <= 200000;
创建每行数据的虚拟列哈希。确保它是NOT NULL
alter table mattmsi add compliance_hash generated always as ( dbms_crypto.hash(to_clob(inventory_item_id || segment1 || last_update_date || created_by || description), 3 /*dbms_crypto.hash_sh1*/) ) VIRTUAL not null ;
在虚拟列上创建索引；这样你就可以通过窄索引的完整扫描而不是胖表的完整扫描来计算哈希值
create index msi_compliance_hash_n1 on mattmsi (compliance_hash);
将它们放在一起来计算您的哈希值
SELECT matt_hash_aggregate(compliance_hash) from (select compliance_hash from mattmsi order by compliance_hash);
一些评论：
- 我认为使用哈希来计算聚合很重要
（而不是仅仅做一个
SUM()在行级哈希上，
因为攻击者可以很容易地伪造正确的金额。
- 我认为你不能（容易？）使用并行查询因为它是
重要的是，将行馈送到聚合函数中
顺序一致，否则哈希值会改变。
