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对于大量的数据来说用变量做参数显然是不合适的，于是在系统设计时创建了实体层，实体层是面向对象设计思想中最基本的类，把大量的数据进行封装，在这里起到数据的实体化存储作用。

For large amounts of data is done with variable parameters is clearly inappropriate, so the system is designed to create a physical layer, physical layer is the most basic object-oriented design classes, a large amount of data is encapsulated in play here the role of the physical storage of data. In VFP test database system physical layer is defined as ExaminationSystemModels, which contains the Question, User, Test three entity classes, the questions, the user, papers were materialized. The property contains questions question number, question text, the correct answer to questions, questions of the number of questions, questions, questions belong part, the questions were entered number, add questions of the time, last modification time for questions. User attributes, including user ID, user name, password, user type. The properties include papers papers number, determine the question set, a collection of multiple-choice questions, the program read the title set, fill in the blank collection, create paper time. Physical layer simultaneously presentation layer, business logic, data access layer references.

Yewuluojiceng ExaminationSystemBLL contains QuestionManager, UserManager, TestManager three class files. In which the legitimacy implement user authentication, the data optimization processing. VFP test database system's data structure is relatively simple and does not require a lot of data processing can be directly stored in the database. Only part of the data access layer incoming data need to go through the data dictionary translations rendered after the presentation layer. In VFP test database system's data dictionary definition of the questions section belongs, item types, user type INT types of numbers to represent. Therefore, business logic will translate these fields for the user to understand the expression.
VFP试题库系统的数据库在设计师应该满足用户的各种应用需求，并且能够高效、安全的存储数据。在概念设计阶段针对试题、试卷、用户等信息建立抽象的概念数据模型，使之能够真实的反映试题、试卷等的属性、联系以及相互的制约情况。
VFP Test System database designer should satisfy various application needs, and can be efficient and secure data storage. In the conceptual design phase for questions, papers, and other information the user to establish an abstract conceptual data model so that it can reflect the real questions, papers and other property, contact and mutual constraints situation. Next, the logical data model design will be designed as a logical database model. Finally, according to SQL server provides storage structures and access methods selected specific physical storage structure is as follows:
(A) examination table (TblQuestion)
Including the question number, item hexadecimal number, the correct answer questions, answers several questions, questions, questions section, entry number, add questions time and time modify the questions.
(2) Paper structure table (TblTest)
Including paper number, title number of software infrastructure part of the judgment, the software part of multiple-choice questions based on the number of multiple-choice program design part number, program design part number reading program title, program design part number fill in the blank, add paper time, and finally modification time.
(3) Paper relational tables (TblTestQuestion)
Including papers number, item number, item scores.
(4) user table (TblUser)
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