Chapter 1

Size: px

Start display at page:

Download "Chapter 1"

轴罔吴
7 years ago
Views:

1 Chapter 10 Object-Oriented Database Management 物件導向式資料庫管理 Fundamentals of Database Management Systems by Mark L. Gillenson, Ph.D. University of Memphis Modified by Walter Chen Dept. of Civil Engineering National Taipei University of Technology Presentation by: Amita Goyal Chin, Ph.D. Virginia Commonwealth University For classroom teaching purpose John Wiley & Sons, Inc.

2 Chapter Objectives List several limitations in the relational database model. 列出關連式資料庫的幾項限制 Describe the object-oriented database concept. 描述物件導向式資料庫的概念 Model data using such complex relationships as generalization and aggregation, and such concepts as inheritance and polymorphism. 使用複雜的方式如一般化聚合化繼承變形來模擬資料 10-2

3 Chapter Objectives Describe the benefits of encapsulation. 描述封裝的好處 Describe the value of developing abstract data types. 描述發展抽象資料型態的價值 Explain what an object/relational database is. 說明何是物件關連式資料庫 10-3

4 Hnedak Bobo Group A leading architecture and design firm headquartered in Memphis, TN. 總部在曼菲斯的建築設計公司 Uses a relational database application called the Contact Management and Lead Tracking System to keep track of its customers, potential customers, and potential projects or leads. 使用關連式資料庫工具管理客戶和線索 10-4

5 10-5

6 Peabody Marching Ducks Five Mallard ducks are housed in the "Duck Palace" on the hotel roof Every day at 11 a.m., they are led down the elevator to the Italian travertine marble fountain in the Peabody Grand Lobby The ceremony is reversed at 5 p.m. Each team lives in the hotel for only three months before being retired from their Peabody duties and returned to the farm to live out the remainder of their days as wild ducks

7 Hnedak Bobo Group cont d The system is stored as an MS Access relational database running on a Compaq server. The system was implemented in It employs canned, menu-based queries written in Visual Basic. The main database tables are a Contact table with 5,500 records and an Events table that tracks every meeting, telephone call, etc. with each contact. 主要的表格是聯絡人表格其中有 5,500 筆資料以及事件表格追蹤紀錄和聯絡人的所有會議電話通話等資料 10-7

8 Historically Speaking For much of IS history the emphasis was on the programs, with the data structures and ultimately the data stored in them being a secondary consideration. The IS environment is changing from this program-centric mentality into a more datacentric one. 以程式為中心變成以資料為中心 10-8

9 Object Orientation 物件導向 An alternative approach to information systems and IS development. 另一種選擇 Began during the 1980s. More data-centric. 更是以資料為中心 10-9

10 What s Missing in the Relational Database Concept? 關連式資料庫缺什麼 Many people would say that nothing is missing from the relational model. 很多人會說什麼都不缺 Others would point out that for certain kinds of complex applications, the relational model is lacking in support for the more complex data model features they need. 有些人會說對某些複雜的應用程式而言關連式模型欠缺對複雜資料模型的支援 10-10

11 What s Missing in the Relational Database Concept? 關連式資料庫缺什麼 Does not directly provide support for generalization/specialization. 不直接支援一般化和特殊化 Does not directly provide support for aggregation. 不直接支援集合體由小的實體組合成大的實體 10-11

12 What s Missing in the Relational Database Concept? 關連式資料庫缺什麼 Does not have a system in which only a limited, controlled set of program segments is allowed to update particular data. 不是只有特定的程式片段可以更動資料 Does not directly support more complex data types such as: 不提供以下資料型態的支援 graphic images 圖形 photo images 照片 video clips 視訊 audio clips 音訊 long text documents 長的文件 mathematical constructs such as matrices 矩陣 10-12

13 Terminology: Object-Oriented Data Modeling 物件導向式資料模型 Object - describes an advanced data structure that includes an entity s attributes 屬性 plus methods or operations or procedures (program code!) that can operate on and modify the object s attribute values. 所謂 object 是一種資料結構其中包含屬性和方法程式程式可以修改物件的屬性資料 (object) class - the objects that describe similar entities. 物件類別描述類似的實體 10-13

14 OODBMS 和 RDBMS 的比較 Entity vs. instance 實體 vs. 實例 Class vs. object 類別 vs. 物件 10-14

15 More advantages of Object Oriented Database Concept 物件導向式資料庫的好處 Each object has an object identifier that is permanent and unique among all objects of all types in the system. 在系統所有種類的物件中每一個物件都有獨特的編號 Some OODBMSs are implemented as pointer-based systems. 有些 OODBMSs 是以指標為基礎的系統 related objects are connected by their storage addresses. 相關物件由它們的儲存地址相連結 OODBMSs are the most natural data storage vehicles when object-oriented programming languages, such as C++, Smalltalk, and Java, are in use. 物件導向式資料庫最適合配合物件導向式程式語言使用 10-15

16 Unified Modeling Language (UML) Introduced in 1997 by the Object Management Group (OMG) Has nine standard diagrams that describe: 有九個標準圖 the system s data 系統資料 the business processes 商業過程 the intended results 預期結果 the components of the program code 程式碼 the hardware and software architectures. 軟硬體架構 10-16

17 UML Class Diagram 類別圖 Describes the system s data, including attributes of and relationships between the objects. 描述系統資料包含物件屬性和物件間關係 10-17

18 Generalization 一般化 Also known as generalization/specialization 一般化或特殊化 Is a relationship that recognizes that some kinds of entities can be subdivided into smaller, more specialized groups. 某些實體可以進一步分割成更小的組別 10-18

19 General Hardware Company ERD General Hardware company E-R diagram. General Hardware is a wholesaler

20 General Hardware Company Generalization Diagram Each box represents a class and has three sections separated by horizontal lines. 每一個方塊代表一個類別有三個部分 At the top, in capital letters, is the class name 類別名稱 In the middle are the class attributes 類別的屬性 At the bottom are the class operations (not shown) 類別的操作方法

21 General Hardware Company Generalization Diagram The upward pointing arrows indicate generalizations. 往上的箭頭代表一般化 There are three kinds of products 三種產品 TOOLs 工具 LIGHT FIXTUREs 燈飾 LUMBER 木材 There are two kinds of tools POWER TOOLs 動力式工具 NONPOWER TOOLs 非動力式工具

22 Inheritance of Attributes 屬性的繼承 The PRODUCT class indicates that all products have three common attributes: Product Number, Product Name, and Unit Price. 所有的產品都有三種共同的屬性 All of the classes below PRODUCT inherit the attributes shown in PRODUCT. 所有下層的類別都繼承由 PRODUCT 而來的屬性 10-22

23 Inheritance of Attributes The attributes for POWER TOOLs are: (from Product) Product Number Product Name Unit Price (from TOOL) Weight (from POWER TOOL) Amperes 安培 10-23

24 Inheritance of Attributes The attributes for NONPOWER TOOLs are (from Product) Product Number Product Name Unit Price (from TOOL) Weight (from NON-POWER TOOL) Years of Warranty 10-24

25 Inheritance of Attributes The attributes for LIGHT FIXTUREs are (from Product) Product Number Product Name Unit Price (from LIGHT FIXTURE) Number of Bulbs Watts per Bulb 10-25

26 Inheritance of Attributes The attributes for LUMBER are (from Product) Product Number Product Name Unit Price (from LUMBER) Type of Wood Dimensions 10-26

27 Operations Operations have now been added to the UML Diagram. There are three kinds of operations: 三種操作方法 Constructor 建造者 Query 查詢 Update 更新 10-27

28 Operations: Constructor 建造者 Creates a new instance of a class, that is, a new object. 產生新的物件 Example: Add Lumber an operation that 產生一個新的木材物件 will add a new instance of LUMBER, that is, a new object, to the database

29 Operations: Query 查詢 Returns data about the values of an object s attributes but does not update them. 提供關於一個物件屬性的資料 Example: Calculate Discount 計算折扣 calculates a discount for a particular customer buying a particular product and returns the result to the user who issued the query, but does not store the result in the database.

30 Operations: Update 更新 Updates an object s attribute values. 更新一個物件的屬性值 Example: Change Unit Price 改變單位價格 a product s unit price may have to be changed, and the result is stored in the database as the new unit price

31 Polymorphism 多形性 Modification or refinement of operations as they are inherited downward. 繼承的過程中改變操作方法 The operations that are performed differently in the lower level objects can have modified names and will perform differently for the different kinds of objects

32 The missing link 47-million-year-old fossil is the earliest ancestor of all living monkeys, apes and people May 19, 2009

33 Polymorphism Looking at Calculate Discount : Since there is nothing more said about the discount further down the hierarchy, the discount is calculated in the same way for all kinds of products. 由於在下層沒有重複出現 Calculate Discount 的計算方法沒有改變 Looking at Calculate Extended Warranty Price : polymorphism occurs in the Calculate Extended Warranty Price operation because it is performed differently for power tools and nonpower tools. 但是 Calculate Extended Warranty Price 產生了變形對兩類工具計算不同 10-33

34 Aggregation 集合體 10-34

35 Aggregation 燈飾燈座燈泡 A class is shown to be composed of other classes. 一個類別是由其他類別所組成 FRAMEs and BULBS are not kinds of LIGHT FIXTUREs; rather, each is a part of a LIGHT FIXTURE

36 General Hardware Company Class Diagram 類別圖 10-36

37 Good Reading Bookstores 的 ER 圖 10-37

38 Good Reading Bookstores Class Diagram 改畫為類別圖 A generalization hierarchy has been created under PRODUCT, which indicates that there are four kinds of products: BOOK, PERIODICAL, CD, and VIDEO/DVD. The PERIODICAL class, and only this class, is associated with the ARTICLE class

39 World Music Association 的 ER 圖 10-39

40 World Music Association Class Diagram A generalization hierarchy has been constructed with subordinate classes ORCHESTRA, CHAMBER GROUP, and JAZZ GROUP. 管弦樂團室內樂團爵士樂團 10-40

41 Lucky Rent-A-Car 的 ER 圖 10-41

42 Lucky Rent-A-Vehicle Class Diagram Lucky Rent-A-Car has expanded to become Lucky Rent-A-Vehicle! A two-level generalization hierarchy under VEHICLE. The diamond-shaped symbol on the branch under the TRUCK class indicates that there is an aggregation diagram under it

43 Encapsulation 用膠囊密封 The attributes of a class or even an individual object are encapsulated, stored together on the disk, with the operations that will act upon them. OODBMS will only permit the attributes of the encapsulated objects to be updated by the encapsulated update-type operations, thereby improving data integrity. 只有被封在一起的操作方法可以用在資料上 10-43

44 Encapsulation When an application program requires encapsulated data, it sends a message to one of the object s encapsulated operations to trigger it into action. 程式通知被封在一起的操作方法進行動作 The application program sends along any input data needed for the operation. 程式也提供輸入資料 10-44

45 Abstract Data Types 抽象資料類別 Object-oriented database allows the creation of new, abstract data types and operations that are associated with them

46 Object/Relational Database OODBMSs were lacking in several areas, including the superior query capabilities of SQL that everyone had become accustomed to. 缺乏 SQL 的優異功能 Relational database and object-oriented database have come together in the form of hybrid relational database management systems with object-oriented features added to them. 成為混合式的資料庫系統 10-46

47 General Hardware Company as an Object/Relational Database 10-47

48 Copyright 2004 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information contained herein

6-7 6-8 6-9 Process Data flow Data store External entity 6-10 Context diagram Level 0 diagram Level 1 diagram Level 2 diagram 6-11 6-12

6-1 6-2 6-3 6-4 6-5 6-6 6-7 6-8 6-9 Process Data flow Data store External entity 6-10 Context diagram Level 0 diagram Level 1 diagram Level 2 diagram 6-11 6-12 6-13 6-14 6-15 6-16 6-17 6-18 6-19 6-20 6-21