computers © 2005 prentice-hall, inc.slide 1. computers chapter 10 information systems development (...

Computers

© 2005 Prentice-Hall, Inc. Slide 1

Computers

Chapter 10

Information Systems Development ( 開發 ) and Programming ( 程式設計 )


ComputersChapter 10 – Information Systems

Development and Programming

ObjectivesDescribe ( 描述 ) the four stages ( 階段 ) of the system life cycle ( 系統生命週期 ).List the basic system development techniques.Understand the scope ( 範圍 ) and capabilities of CASE (Computer-Aided Software Engineering ( 軟體工程 )).


ComputersChapter 10 – Information Systems

Development and Programming

ObjectivesExplain the concepts and phases of prototyping ( 雛形發展 ).Discuss approaches ( 方法 ) to converting ( 轉換 ) to a new system.Describe the basic programming concepts, techniques, and languages ( 語言 ).


ComputersInformation Systems Development and

ProgrammingThe System Life Cycle

Birth ( 出生 ) – someone has an idea about how to use a computerDevelopment – IT professionals ( 專業人員 ) and users work to design ( 設計 ) the system Production ( 生產 ) – the information system becomes operational ( 運作 ) End-of-life – no longer ( 不再 ) feasible ( 可行性 ) to maintain ( 維護 ) the system



ProgrammingInformation System Development Options ( 選擇 )

Purchase ( 購買 ) an information systemProprietary ( 專有 ) information system – developed by a vendor ( 廠商 ) for a specific audience ( 觀眾 )

Outsourcing ( 委外 ) to an application service provider (ASP ，應用系統服務提供者 )

ASP provides software-based services and solutions



ProgrammingInformation System Development Options

Develop a custom ( 客製化 ) information system

Turnkey ( 統包 ) system – created by outside consultants ( 顧問公司 )



ProgrammingSystem Development Techniques and Concepts

Structured system design ( 結構化系統設計 ) – top-down design technique　

Structure chart ( 結構圖 ) – system displayed ( 顯示 ) as a hierarchy ( 階層 ) of modules( 模組 )




Data flow diagram ( 資料流動圖 ) – shows how data flows through the system




Data flow diagram – uses four symbols 　 ( 符號 )

Entity ( 個體 ) symbol– shows source or destination of data or informationProcess ( 處理 ) symbol – describes a function to be performedFlow line ( 流向線 ) – shows the direction in which data or information is flowingData storage – identifies storage locations




Entity relationship diagram ( 實體關聯圖 ) – shows the attributes ( 屬性 ) of entities and the relationship between them



Programming Computer-Aided Software 　Engineering

Software engineering – software 　development that uses automation ( 自動化 ) and the rigors ( 嚴謹性 ) of engineering ( 工程方法 )CASE – Computer-Aided Software　 Engineering



ProgrammingComputer-Aided Software 　Engineering

Software engineers – develop software Custom programming – writing of 　original programs



ProgrammingCASE Tools

Design toolsUser interface ( 人機介面 )Screen generator ( 螢幕畫面產生器 )Report generator

Layout ( 佈局 ) – detailed input and/or output specifications ( 規格 )




Information Repository ( 庫 ) ToolsInformation repository – central ( 中央 ) computer-based storage facility ( 設施 )Database for the system development project ( 計畫 )




Program Development ToolsApplication generator ( 應用程式產生器 ) – works with design specifications and database structure to generate software for a particular ( 特定 ) application



ProgrammingPrototyping

Prototype system – a model ( 模型 ) of a full-scale ( 全形的 ) systemPrototyping – using this approach in applications development




Typical prototype system Handles main transaction-oriented ( 為導向 ) proceduresProduces common ( 共同 ) reportsPermits ( 允許 ) typical interactions to the 　 database




Scalable ( 可攀升功能的 ) system – can handle any size database or any number of users




System Development Life Cycle (SDLC) – used before CASE was developed

System specifications – managers had to commit ( 認可 ) to these specifications early in the creation of the system




The Prototype System ObjectivesAnalyze the current situation ( 狀況 )Identify information needsDevelop a model of the proposed system (target system)




Rapid ( 快速 ) Application Development (RAD) – generic ( 通用 ) reference ( 參考 ) to using software tools (CASE) to design, develop, and implement information systems




The Prototyping ProcessPhase I – Define system specifications ( 系統規格 )Systems analysis ( 系統分析 ) – understanding the system

Existing system review ( 審查 )System objectives ( 系統目標 )Design constraints ( 設計限制 )Requirements definition ( 需求定義 )




The Prototyping ProcessPhase I – Define system specifications

System design ( 系統設計 ) – relationships ( 關係 ) between various ( 各種 ) components of the system are defined




The Prototyping ProcessPhase II – Create prototype system

Software creation is main job




The Prototyping ProcessPhase III – Refine ( 精化 ) prototype system

Changes ( 改變 ) are made, based on user input




The Prototyping ProcessPhase IV – Develop operational ( 運作 ) system

System is scaled ( 提升 ) to necessary ( 必需的 ) size



ProgrammingSystem Conversion and Implementation

Systems and Acceptance Testing ( 接收測試 )

Unit ( 單元 ) testing – testing of individual ( 個別的 ) software unitsSystems testing – making sure ( 確定 ) the software units work together ( 一起 )



ProgrammingApproaches to System Conversion ( 轉換 )

Parallel ( 並行 ) conversion – old and new systems are run side-by-side until the project team is confident ( 信心 ) the new system worksDirect ( 直接 ) conversion – old system is 　abandoned ( 放棄 ) as soon as the new system　 is ready 　



ProgrammingApproaches to System Conversion

Phased ( 分階段 ) conversion – using parallel or direct conversion to 　implement one module at a timePilot ( 分區 ) conversion – using parallel, direct, or phased conversion to　 implement the system in one area at a 　 time



ProgrammingThe System Becomes Operational ( 可運作 )

Emphasis ( 強調 ) switches ( 切換 ) from development ( 開發 ) to operations ( 運轉 )System maintenance – process of modifying ( 改變 ) the system to meet ( 滿足 ) changing needsPatches ( 修補 ) – modifications to the system



ProgrammingProgramming

Custom programming – creating programs to support an information systemProgrammers – people who write programsProgramming languages – languagesused to give instructions ( 指令 ) to the computer



ProgrammingSoftware in Perspective ( 概視 )

Used to solve a problemLogic for solving a problem must be developed



ProgrammingSoftware in Perspective

Types of computer instructionsInput/outputComputational ( 計算 )Control ( 控制 )



ProgrammingTypes of Programming Languages

Machine ( 機器 ) language – low-level

Source ( 來源 ) program – original ( 原始 ) program created by programmerObject ( 目的 ) program – machine-language version of the program




Machine language – low-level Compiler ( 編譯器 ) – converts ( 轉換 ) the source program into the object programInterpreter ( 直譯器 ) – converts source program and executes ( 執行 ) the instructions one instruction at a time




Procedure-oriented ( 步驟導向 ) languages – required programs to solve problems using traditional ( 傳統 ) programming logicInstructions are coded ( 編碼 ) or writtenCOBOL – business purposes ( 目的 )FORTRAN – scientific ( 科學 ) purposes




Object-oriented ( 物件導向 ) programming (OOP) makes programs easier to design and understand ( 了解 )OOP and object-oriented languages –emphasis is on the object of the action ( 動作 ) C++Java




Object – self-contained ( 自給自足 ) module ( 模組 ) that describes ( 描述 ) data and the methods ( 方法 ) for manipulating ( 處理 ) the dataObjects are grouped ( 群組 ) into classes ( 類 ) and subclasses ( 次類 )Inheritance ( 繼承 ) – attributes ( 屬性 ) are passed on to subclasses




Fourth generation ( 年代 ) languages 　(4GLs) – use high-level English-like instructions to retrieve ( 擷取 ) and format ( 格式 ) dataQuery ( 查詢 ) languages – allow users to request ( 要求 ) information directly from a database


select employee_last_name, employee_first_name from employee, department where employee_department_code = department_code and deparment_description like ‘ACT%’ order by employee_last_name



Visual ( 圖像式 ) languages – text-based 　 instructions are replaced ( 取代 ) with 　 symbolic ( 符號 ) icons ( 圖像 )

Visual BASICVisual C#




Macro ( 巨集 ) languages – sequence ( 數列 ) of frequently used operations or keystrokes ( 按鍵 ) that can be recalled ( 召回 ) as needed

Record-and-play Macro language



ProgrammingWriting the Program

System Specifications Review ( 回顧 ) – programs are coded based on system specifications completed ( 完成 ) during the systems analysis and design stages




Program Identification ( 指出 ) and Description ( 描述 ) – all necessary ( 需要 ) modules are identified and described




Program Design, Coding, Testing, and Documentation ( 文件 )

Flowcharting ( 流程圖 ) – symbols and flow lines are used to visually portray ( 描繪 ) the system




Program Design, Coding, Testing, and Documentation

Control structures ( 控制結構 )Sequence – instructions are performed in orderSelection – a decision is made as to which code will be executedLoop – instructions are repeated ( 重複 )





Driver ( 驅動 ) module – main programSubroutines ( 副程式 ) – subordinate programs


Main

Input Process Output




Pseudocode ( 虛碼 ) – represents program logic in program-like statements ( 敘述 ) written in English





Extreme ( 終極 ) programming (XP) –programming teams work together in 　cycles 　

Starts with users’ storiesUses simplest ( 最簡 ) possible ( 可能 ) designPair ( 配對 ) programming


Computers Chapter 10 – Information Systems

Development and ProgrammingLesson Summary

• Describe the four stages of the system life cycle.

• List the basic system development techniques.

• Understand the scope and capabilities of CASE (Computer-Aided Software Engineering).


Computers Chapter 10 – Information Systems

Development and ProgrammingLesson Summary

• Explain the concepts and phases of prototyping.

• Discuss approaches to converting to a new system.

• Describe the basic programming concepts, techniques, and languages.


computers © 2005 prentice-hall, inc.slide 1. computers chapter 10 information systems development (...

Documents

computer development

system production

new system

programming objectives

computers chapter

information process

basic programming concepts

system life cycle birth