安徽工業(yè)大學(xué) 軟件工程 方木云 ch7

1、Notice通知,實(shí)驗(yàn)內(nèi)容：科研管理系統(tǒng)架構(gòu)要求：B/S模式語言要求：Java, C#數(shù)據(jù)庫：SQL Server2005以上進(jìn)度要求：第10周檢查人員要求：一人獨(dú)立完成 可以下載框架進(jìn)行二次開發(fā),Requirement Engineering,1.What is requirement2.How to do requirement3.How to describe

2、 requirement軟件利潤=需求-設(shè)計(jì)人生利潤=？需海無涯,Requirement pre contract合同前需求方法,Through Networks 網(wǎng)絡(luò)上Through Books書籍上Interview with endusers 現(xiàn)場(chǎng)了解,Requirement after contract合同后需求,現(xiàn)場(chǎng)詳細(xì)需求分析利用原型生成中使用的所有單據(jù)都要收集1.橫向單據(jù)2.縱向單據(jù)3.入庫單據(jù)

3、4.出庫單據(jù),How to express Requirements需求后整理表達(dá)方法,分類整理的能力流程整理數(shù)據(jù)單據(jù)的整理兩種方法：面向數(shù)據(jù)流面向?qū)ο?Who act the role誰承擔(dān)需求分析,系統(tǒng)分析員,系統(tǒng)分析員的作用：,developers,users,managers,analyst,prototype,Requirement specification,planning,兩類需求建模：面向數(shù)據(jù)流；面向?qū)?/p>

4、象,To explain why Entity-Relationship Diagram(ERD) is used? ER圖To describe Data Flow Diagram(DFD) 數(shù)據(jù)流圖To introduce some of the notations used in the Unified Modelling Language (UML) 統(tǒng)一建模語言面向過程設(shè)計(jì)： ER圖+數(shù)據(jù)流圖+詳細(xì)

5、設(shè)計(jì)面向?qū)ο笤O(shè)計(jì)：統(tǒng)一建模語言+RUP,面向數(shù)據(jù)流和面向?qū)ο?Entity-Relationship Diagram （ERD）設(shè)計(jì)數(shù)據(jù)庫Data Flow Diagram（DFD）描述系統(tǒng)數(shù)據(jù)流the Unified Modelling Language (UML)采用統(tǒng)一建模語言,Model types模型類型,Entity-Relationship Diagram （ERD）在數(shù)據(jù)庫課程中已講Data Flow

6、Diagram（DFD）主要介紹，實(shí)驗(yàn)報(bào)告中要采用the Unified Modelling Language (UML)新的內(nèi)容，逐漸取代DFD，其內(nèi)容繁多，不是一兩次能講完，因此只介紹框架,Data flow diagrams數(shù)據(jù)流圖,DFDs model the system from a functional perspectiveTracking and documenting how the data associ

7、ated with a process is helpful to develop an overall understanding of the systemData flow diagrams may also be used in showing the data exchange between a system and other systems in its environment,,Process 數(shù)據(jù)加工 (數(shù)據(jù)變

8、換),,Data source or destination 數(shù)據(jù)源點(diǎn)或終點(diǎn) (外部實(shí)體),,Data flow 數(shù)據(jù)流,Data Store 數(shù)據(jù)存儲(chǔ)文件,數(shù)據(jù)流圖中的主要圖形元素,Example 1 描述銀行取款過程的數(shù)據(jù)流圖,分層的數(shù)據(jù)流圖,在多層數(shù)據(jù)流圖中，頂層流圖僅包含一個(gè)加工，它代表被開發(fā)系統(tǒng)。它的輸入流是該系統(tǒng)的輸入數(shù)據(jù)，輸出流是系統(tǒng)所輸出數(shù)據(jù)底層流圖是指其加工不需再做分解的數(shù)據(jù)流圖，它處在最底層中間層流圖則表示對(duì)

9、其上層父圖的細(xì)化。它的每一加工可能繼續(xù)細(xì)化，形成子圖。,Example 2商店業(yè)務(wù)處理系統(tǒng),這個(gè)數(shù)據(jù)流圖只是一個(gè)高層的系統(tǒng)邏輯模型，它反映了目標(biāo)系統(tǒng)要實(shí)現(xiàn)的功能數(shù)據(jù)流圖繪制步驟 首先確定系統(tǒng)的輸入和輸出 根據(jù)商店業(yè)務(wù)，畫出頂層數(shù)據(jù)流圖，以反映最主要業(yè)務(wù)處理流程,Analysis,經(jīng)過分析，商店業(yè)務(wù)處理的主要功能應(yīng)當(dāng)有銷售、采購、會(huì)計(jì)三大項(xiàng)。主要數(shù)據(jù)流輸入的源點(diǎn)和輸出終點(diǎn)是顧客和供應(yīng)商。 然后從輸入端開始，根據(jù)商店業(yè)務(wù)工作流程，

10、畫出數(shù)據(jù)流流經(jīng)的各加工框，逐步畫到輸出端，得到第一層數(shù)據(jù)流圖,Analysis,0層數(shù)據(jù)流圖,1層子數(shù)據(jù)流圖 銷售細(xì)化,1層子數(shù)據(jù)流圖 采購細(xì)化,檢查和修改數(shù)據(jù)流圖的原則,數(shù)據(jù)流圖上所有圖形符號(hào)只限于前述四種基本圖形元素?cái)?shù)據(jù)流圖的主圖必須包括前述四種基本元素，缺一不可數(shù)據(jù)流圖的主圖上的數(shù)據(jù)流必須封閉在外部實(shí)體之間每個(gè)加工至少有一個(gè)輸入數(shù)據(jù)流和一個(gè)輸出數(shù)據(jù)流,在數(shù)據(jù)流圖中

11、，需按層給加工框編號(hào)。編號(hào)表明該加工所處層次及上下層的親子關(guān)系規(guī)定任何一個(gè)數(shù)據(jù)流子圖必須與它上一層的一個(gè)加工對(duì)應(yīng)，兩者的輸入數(shù)據(jù)流和輸出數(shù)據(jù)流必須一致。此即父圖與子圖的平衡可以在數(shù)據(jù)流圖中加入物質(zhì)流，幫助用戶理解數(shù)據(jù)流圖,基本加工邏輯說明,,對(duì)數(shù)據(jù)流圖的每一個(gè)基本加工，必須有一個(gè)基本加工邏輯說明基本加工邏輯說明必須描述基本加工如何把輸入數(shù)據(jù)流變換為輸出數(shù)據(jù)流的加工規(guī)則加工邏輯說明必須描述實(shí)現(xiàn)加工的策略而不是實(shí)現(xiàn)加工的細(xì)節(jié)加工邏

12、輯說明中包含的信息應(yīng)是充足的，完備的，有用的，無冗余的,Data dictionaries數(shù)據(jù)字典,1. Data dictionaries are lists of all of the names used in the system models. Descriptions of the entities, relationships and attributes are also included2. Many CASE

13、 workbenches support data dictionaries3. 數(shù)據(jù)流圖需要數(shù)據(jù)字典來補(bǔ)充說明,數(shù)據(jù)詞典與數(shù)據(jù)流圖配合，能清楚地表達(dá)數(shù)據(jù)處理的要求詞條描述 —— 對(duì)于在數(shù)據(jù)流圖中每一個(gè)被命名的圖形元素，均加以定義，其內(nèi)容有: 名字，別名或編號(hào)，分類，描述，定義，位置，其它，等,Data dictionaries數(shù)據(jù)字典,Description of Data flow數(shù)據(jù)流詞條描述,數(shù)據(jù)流名：說明：簡要介

14、紹作用即它產(chǎn)生的原因和結(jié)果數(shù)據(jù)流來源：來自何方數(shù)據(jù)流去向：去向何處數(shù)據(jù)流組成：數(shù)據(jù)結(jié)構(gòu)數(shù)據(jù)量流通量：數(shù)據(jù)量，流通量Example:訂單=訂單號(hào)+日期+品種+數(shù)量+單價(jià),Description of Data store數(shù)據(jù)文件詞條描述,數(shù)據(jù)文件名：簡述：存放的是什么數(shù)據(jù)輸入數(shù)據(jù)：輸出數(shù)據(jù)：數(shù)據(jù)文件組成：數(shù)據(jù)結(jié)構(gòu)存儲(chǔ)方式：順序，直接，關(guān)鍵碼存取頻率：Example:待訂商品=商品號(hào)+商品名稱+品種+數(shù)量+單價(jià),

15、Description of Process加工邏輯詞條描述,加工名：加工編號(hào)：反映該加工的層次簡要描述：加工邏輯及功能簡述輸入數(shù)據(jù)流：輸出數(shù)據(jù)流：加工邏輯：簡述加工程序，加工順序Example:1.1編輯訂單=增加+刪除+修改+查詢,Description of Data source or destination 源點(diǎn)及匯(終)點(diǎn)詞條描述,名稱：外部實(shí)體名簡要描述：什么外部實(shí)體有關(guān)數(shù)據(jù)流：數(shù)目：Exampl

16、e:顧客=顧客號(hào)+顧客名稱+聯(lián)系電話+法人代表+信譽(yù)度,領(lǐng)書單 進(jìn)書通知,購書單 缺書單,DFD練習(xí)—售書系統(tǒng),領(lǐng)書單　　　　 　　　　　進(jìn)書通知,進(jìn)書通知,購書單　　　　　　　　　　　　　缺書單,DFD練習(xí)—售書系統(tǒng),,,,F1教材存量表,F2缺書登記表,,The Unified Modeling Language統(tǒng)一建模語言,Devis

17、ed by the developers of widely used object-oriented analysis and design methodsHas become an effective standard for object-oriented modellingNotationObject classes are rectangles with the name at the top, attributes i

18、n the middle section and operations in the bottom sectionRelationships between object classes (known as associations) are shown as lines linking objectsInheritance is referred to as generalisation and is shown ‘upwards

19、’ rather than ‘downwards’ in a hierarchy,Object aggregation,Aggregation model shows how classes which are collections are composed of other classesSimilar to the part-of relationship in semantic data models,Object aggre

20、gation,Object behaviour modelling,A behavioural model shows the interactions between objects to produce some particular system behaviour that is specified as a use-caseSequence diagrams (or collaboration diagrams) in th

21、e UML are used to model interaction between objects,Issue of electronic items,CASE workbenches,A coherent set of tools that is designed to support related software process activities such as analysis, design or testingA

22、nalysis and design workbenches support system modelling during both requirements engineering and system designThese workbenches may support a specific design method or may provide support for a creating several differen

23、t types of system model,An analysis and design workbench,Analysis workbench components,Diagram editorsModel analysis and checking toolsRepository and associated query languageData dictionaryReport definition and gene

24、ration toolsForms definition toolsImport/export translatorsCode generation tools,Key points(主要知識(shí)點(diǎn)),A model is an abstract system view. Complementary types of model provide different system informationContext models s

25、how the position of a system in its environment with other systems and processesData flow models may be used to model the data processing in a systemState machine models model the system’s behaviour in response to inte

26、rnal or external events,Key points,Semantic data models describe the logical structure of data which is imported to or exported by the systemsObject models describe logical system entities, their classification and aggr