因为把数据存放在被使用位臵上是很合乎常理的。例如一个大公司不同部门之间的计算机，应该将数据存储在本地，然而，当被授权的管理人员需要整理部门数据时，数据应该能够被访问。数据库信息系统软件将保护数据库的安全性和完整性，对用户而言，分布式数据库和非分布式数据库看起来没有什么差别。 在这个信息时代，数据管理服务器已经成为公司的核心。这一个软件的模块控制整个组织的顺利运行就如同人身体动脉使得鲜血在身体中流通顺畅。因为这个所以就要把好身份申请这一关，数据管理服务器也是黑客最为关心的目标之一。如果一旦自己的身份验证被黑客攻克,他将能引起公司的 \心脏\遭受致命的破坏。 虽然大多数的使用者现在知道黑客，但是他们仍然不了解他们的数据库伺候器是多么的易受影响黑客的攻击。因此，这篇文章介绍是如何攻击数据库伺候器 (比如 SQL 伺候器) 和讲述你在受攻击时该如何保护你自己的数据。 我们应该注意信息不断更新。许多技术上的空白导致了 SQL 在运行时很多细节被攻击的事，而且很多的易受攻击的地方被寄到完全地描述数据库申请能是多么的某开发的安全目录。 这个文章对那些好奇的非 SQL 专家是书面的不关心知道细节，而且如检讨到那些做的人有规则地使用 SQL。 一个 SQL 伺候器是做什么的， 一个数据库身份验证是一个提供给有权限客户访问数据通道。申请的类型有许多变化,从大企业的微软 SQL 伺候器到自由的和开放来源 mySQL 排列。不管是什么，大多数的数据库伺候器申请都有共同的一些功能。 首先，数据库申请使用都使用相同的 SQL 的语言，或结构查询语言。这些语言，也属于第四代语言，由于它单纯化的语法，是在一位客户如何向伺候器传达它的请求核心。使用它最简单的形式语言 SQL，一个程序师能选择,增加、更新、而且在一个数据库中能划分各种数据。然而，SQL 也能用来产生并且设计整个的数据库，运行被送回的数据上的各种不同的功能,甚至运行其他的程序。 为了要举例说明 SQL 如何使用,下列各项是简单标准 SQL 的一个例子疑问和一个比较复杂的 SQL 疑问， 简单的 \挑选出来的，从 dbFurniture.tblChair\这在来自数据库 dbFurniture 的数据库 tblChair 中返还的所有数据. 复杂:\管理人员征服。 xp_cmdshell'dir c 。:\\'\这个短 SQL 指令回到客户文件和文件夹的目录在 SQL 伺候器的 c:\\directory 之下，注意这个例子使用一个广大的储存对 MS SQL 伺候器是独家的程序。 第二个功能数据库伺候器申请部份是他们全部需要一些形式的验证进行建立客户和主机之间的连接。虽然 SQL 语言基本语法形式使用中很容易。他只要建立一些基础的形式就行了，想要运行任何客户的疑问一定要首先提供一些形式，这将会授权与客户的国书，客户也要有一定的定义请求和回应的格式。 这个连接被一些属性定义,仰赖客户的相关位臵和什么操作系统是在使用中， 我们可以花费整个文
5
章讨论例如， DSN 连接，较少的 DSN-连接RDO 费力和更多的各种不同的技术，但是这些主题超过了这个文章的范围。如果你想要学习更多有关他们，一些 Google'ing 将会提供更充足的数据给你。 然而，下列各项是被包含在关系中一些连接请求的一连串的比较通常的项目。 数据库来源、 请求类型、 数据库 、 使用者身份证、 密码 、任何的连接在连接之前，客户要连接到什么类型的伺候器。这被一个提供被需要在正确的格式中产生请求的指令给客户的软件成份处理。除了数据库的类型，请求类型能用来比较进一步定义客户的请求将会如何被伺候器处理。下一个来数据库名字和最后证明数据。 所有的连接信息都很重要，但是显然最弱的联编是关于证明数据或缺乏。在适当地处理了伺候器。每个数据库明确地用有它的自己使用者指定了控制他们能运行什麽类型的活动许可。举例来说，一个使用者帐户会是建立如申请所只有读哪一对唯一的通路数据需要。另外的一个帐户应该作为插入物或更新，而且也许甚至一个第三帐户会是使用过的因为划除。帐户控制的这个类型确定那个任何的被妥协处理的帐户在功能性中被限制。不幸地，许多数据库计画是建立由于无效力的或容易的密码，导致成功的攻击。 书名：Modern Database Management 作者：Jeffrey A. Hoffer, Mary B. Prescott, Fred R. McFadden 出版社：Prentice Hall 2005 ISBN: 0131453203 9780131453203 指导教师审阅意见： 指导教师： 年 月 日
6
外文资料
Database Management Systems A database (sometimes spelled data base) is also called an electronic database , referring to any collection of data, or information, that is specially organized for rapid search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval , modification, and deletion of data in conjunction with various data-processing operations .Databases can be stored on magnetic disk or tape, optical disk, or some other secondary storage device. A database consists of a file or a set of files. The information in these files may be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage , and each field typically contains information pertaining to one aspect or attribute of the entity described by the database . Using keywords and various sorting commands, users can rapidly search , rearrange, group, and select the fields in many records to retrieve or create reports on particular aggregate of data. Complex data relationships and linkages may be found in all but the simplest databases .The system software package that handles the difficult tasks associated with creating ,accessing, and maintaining database records is called a database management system(DBMS).The programs in a DBMS package establish an interface between the database itself and the users of the database.. (These users may be applications programmers, managers and others with information needs, and various OS programs.) A DBMS can organize, process, and present selected data elements form the database. This capability enables decision makers to search, probe, and query database contents in order to extract answers to nonrecurring and unplanned questions that aren’t available in regular reports. These questions might initially be vague and/or poorly defined ,but people can “browse” through the database until they have the needed information. In short, the DBMS will “manage” the stored data items and assemble the needed items from the common database in response to the queries of those who aren’t programmers. A database management system (DBMS) is composed of three major parts:(1)a storage subsystem that stores and retrieves data in files;(2) a modeling
7
and manipulation subsystem that provides the means with which to organize the data and to add , delete, maintain, and update the data;(3)and an interface between the DBMS and its users. Several major trends are emerging that enhance the value and usefulness of database management systems; Managers: who require more up-to-data information to make effective decision Customers: who demand increasingly sophisticated information services and more current information about the status of their orders, invoices, and accounts. Users: who find that they can develop custom applications with database systems in a fraction of the time it takes to use traditional programming languages. Organizations : that discover information has a strategic value; they utilize their database systems to gain an edge over their competitors. The Database Model A data model describes a way to structure and manipulate the data in a database. The structural part of the model specifies how data should be represented(such as tree, tables, and so on ).The manipulative part of the model specifies the operation with which to add, delete, display, maintain, print, search, select, sort and update the data. Hierarchical Model The first database management systems used a hierarchical model-that is-they arranged records into a tree structure. Some records are root records and all others have unique parent records. The structure of the tree is designed to reflect the order in which the data will be used that is ,the record at the root of a tree will be accessed first, then records one level below the root ,and so on. The hierarchical model was developed because hierarchical relationships are commonly found in business applications. As you have known, an organization char often describes a hierarchical relationship: top management is at the highest level, middle management at lower levels, and operational employees at the lowest levels. Note that within a strict hierarchy, each level of management may have many employees or levels of employees beneath it, but each employee has only one manager. Hierarchical data are characterized by this one-to-many relationship among data. In the hierarchical approach, each relationship must be explicitly defined when the database is created. Each record in a hierarchical database can contain
8
