【正文】 t add the field to a table if it will result in the same information appearing in multiple records in that table. If you determine that a field in a table will contain a lot of duplicate information, that field is probably in the wrong table. For example, if you put the field containing the address of a customer in the Orders table, that information will probably be repeated in more than one record, because the customer will probably place more than one order. However, if you put the address field in the Customers table, it will appear only once. In this respect, a table in a Microsoft Access database (Microsoft Access database: A collection of data and objects (such as tables, queries, or forms) that is related to a particular topic or purpose. The Microsoft Jet database engine manages the data.) differs from a table in a flat file database such as a spreadsheet. When each piece of information 。t create an additional field that multiplies the values in these two fields. ? Don39。t create fields for data that consists of lists of multiple items. For example, in a Suppliers table, if you create a Products field that contains a maseparated list of each product you receive from the supplier, it will be more difficult to find only the suppliers that provide a particular product. ? Don39。d like the database to produce. ? Gather the forms you currently use to record your data. As you determine the purpose of your database, a list of information you want from the database will begin to emerge. From that, you can determine what facts you need to store in the database and what subject each fact 陜西理工學院畢業(yè)設計 belongs to. These facts correspond to the fields (columns) in your database, and the subjects that those facts belong to correspond to the tables. Determine the fields you need in the database Each field is a fact about a particular subject. For example, you might need to store the following facts about your customers: pany name, address, city, state, and phone number. You need to create a separate field for each of these facts. When determining which fields you need, keep these design principles in mind: ? Include all of the information you will need. ? Store information in the smallest logical parts. For example, employee names are often split into two fields, FirstName and LastName, so that it39。s a good idea to sketch out and rework your design on paper first. You can also examine welldesigned databases similar to the one you are designing, or you can open the Northwind sample database and then open the Relationships window (Relationships window: A window in which you view, create, and modify relationships between tables and queries.) to examine its design. Follow these basic steps when designing your database. Determine the purpose of your database The first step in designing a database is to determine its purpose and how it39。 陜西理工學院畢業(yè)設計 參考文獻 [1] Craig Eddy ， Timothy Buchanan. 中文 Access 2021 24 學時教程 [M].北京： 機械工業(yè)出版社 ， [2] Steven Holzner . Visual Basic 6 技術內(nèi)幕 [M].詳實翻譯組 .北京： 機械工業(yè)出版社 ， [3] 懂國平，顏志軍，萬麗 .Visual Basic 數(shù)據(jù)庫開發(fā) [M].北京： 電子 工業(yè)出版社 ， [4] 劉炳文 .Visual Basic 程序設計教程（第二版） [M] .北京 :清華大學出版社， [5] 高容芳，張曉濱，趙安科 .數(shù)據(jù)庫原理 [M].西安 :西安電子科技大學出版社， [6] 任勝兵，邢琳 .軟件工程 [M].北京 :北京郵電大學出版社， [7] VB 學習網(wǎng) . [8] [9] Hernandez, Michael J. Database Design for Mere Mortals: A Hands On Guide to Relational Database Design, Second Edition. AddisonWesley Professional. 2021. 陜西理工學院畢業(yè)設計 科技外文文獻 Introduction Of Visual Basic Program And Access A Visual Basic program is built up from standard building blocks. A solution prises one or more projects. A project in turn can contain one or more assemblies. Each assembly is piled from one or more source files. A source file provides the definition and implementation of classes, structures, modules, and interfaces, which ultimately contain all your code. FileLevel Programming Elements When you start a project or file and open the code editor, you see some code already in place and in the correct order. Any code that you write should follow the following sequence: statements statements statements and namespacelevel elements If you enter statements in a different order, pilation errors can result. A program can also contain conditional pilation statements. You can intersperse these in the source file among the statements of the preceding sequence. Option Statements Option statements establish ground rules for subsequent code, helping prevent syntax and logic errors. The Option Explicit Statement (Visual Basic) ensures that all variables are declared and spelled correctly, which reduces debugging time. The Option Strict Statement helps to minimize logic errors and data loss that can occur when you work between variables of different data types. The Option Compare Statement specifies the way strings are pared to each other, based on either their Binary or Text values. Imports Statements You can include an Imports Statement to import names defined outside your project. An Imports statement allows your code to refer to classes and other types defined within the imported namespace, without having to qualify them. You can use as many Imports statements as appropriate. Namespace Statements Namespaces help you anize and classify your programming elements for ease of grouping and accessing. You use the Namespace Statement to classify the following statements within a particul