从数据行入手保护SQL Server数据安全

在当今企业环境中，保证数据安全不是可有可无的工作。频繁曝光的入侵和欺骗事件、萨班斯•奥克斯利法案、HIPAA法案规定和爱国者法案等都要求我们能够做到，将正确数据提供给正确的用户，防止其它无权限的人访问。一般来说，“行级安全(row-level security)”的要求是：对数据库中的数据以行为单位，设定只有特定用户才可以访问。可惜的是，SQL Server数据库并不提供内置的行级别安全机制。

在本篇文章中，通过一个示例代码(代码清单1)，来告诉大家一个在SQL Server中实现行级别安全的方法，以行为单位限定用户的访问权限，同时无需修改业务表的内容，不影响应用程序或表现层开发者，而且与用户访问数据的方式无关。该示例应用的模拟需求为：如何增加安全性到现有订单数据库中，限制经理只能访问他们管理的部门或其子部门的数据，而不管用户如何获得该表，以及针对这个数据库开发什么样的报表和查询。

以下为引用的内容：

--create table script
CREATE TABLE dbo.UserAccess
(
UserID varchar(20) NOT NULL,
Department varchar(50) NOT NULL
)
CREATE TABLE [dbo].[Orders](
[OrderID] [int] NOT NULL,
[CustomerName] [varchar](20) NOT NULL,
[OrderTotal] [money] NOT NULL,
[Department] [varchar](50) NOT NULL
)
CREATE TABLE dbo.Departments
(
Department varchar(50) NOT NULL,
ParentDepartment varchar(50)
)
--end create table script

--script to clear then populate example tables

--clear tables
Delete from departments
Delete from orders
Delete from useraccess

--insert departments table
INSERT  INTO [dbo].[Departments] ([Department],[ParentDepartment]) VALUES ('North America','')
INSERT INTO [dbo].[Departments] ([Department],[ParentDepartment]) VALUES ('East','North America')
INSERT INTO [dbo].[Departments] ([Department],[ParentDepartment]) VALUES ('Southeast','East')
INSERT INTO [dbo].[Departments] ([Department],[ParentDepartment]) VALUES ('Northeast','East')
INSERT INTO [dbo].[Departments] ([Department],[ParentDepartment]) VALUES ('West','North America')
INSERT INTO [dbo].[Departments] ([Department],[ParentDepartment]) VALUES ('Southwest','West')
INSERT INTO [dbo].[Departments] ([Department],[ParentDepartment]) VALUES ('Northwest','West')

--insert orders table
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (1,'Harris','11.00','East')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (2,'Corrigan','22.00','Southeast')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (2,'Corrigan','22.00','Southeast')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (3,'Baldwin','33.00','Southeast')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (4,'Pillow','44.00','Northeast')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (5,'Carpenter','55.00','Northeast')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (6,'Meyer','66.00','West')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (7,'Gonzalez','77.00','Southwest')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (8,'Hall','88.00','Northwest')
INSERT INTO [dbo].[Orders] ([OrderID],[CustomerName],[OrderTotal],[Department]) VALUES (9,'Patrick','99.00','Southwest')

--insert user access table
INSERT INTO [dbo].[UserAccess] ([UserID],[Department]) VALUES ('BLambert','Southwest')
INSERT INTO [dbo].[UserAccess] ([UserID],[Department]) VALUES ('MDavis','East')
INSERT INTO [dbo].[UserAccess] ([UserID],[Department]) VALUES ('MDavis','Southeast')
INSERT INTO [dbo].[UserAccess] ([UserID],[Department]) VALUES ('MDavis','Northeast')
INSERT INTO [dbo].[UserAccess] ([UserID],[Department]) VALUES ('WSimmons','Northeast')

--end script to clear then populate example tables

代码清单1：提供了创建和加载示例表的脚本