Chapter 1 © 2013 Pearson Education CHAPTER 1: THE DATABASE ENVIRONMENT AND DEVELOPMENT PROCESS Modern…

Chapter 1 © 2013 Pearson Education© 2013 Pearson Education

CHAPTER 1:CHAPTER 1:THE DATABASE ENVIRONMENT AND THE DATABASE ENVIRONMENT AND DEVELOPMENT PROCESSDEVELOPMENT PROCESS

Modern Database Management11th Edition, International EditionJeffrey A. Hoffer, V. Ramesh, Heikki Topi

© 2013 Pearson Education1


Chapter OutlineChapter Outline ExamplesExamples of Developing a Database of Developing a Database

ApplicationApplication Basic Concepts and DefinitionsBasic Concepts and Definitions Traditional File Processing SystemsTraditional File Processing Systems The Database ApproachThe Database Approach Components of the Database EnvironmentComponents of the Database Environment The Database Development ProcessThe Database Development Process Evolution of Database SystemsEvolution of Database Systems The Range of Database ApplicationsThe Range of Database Applications

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工作流程的自動化與優化中鋼薪資發放流程的案例

上下班的簽到簽退管理 ( 以前 : 打卡，現在 : ?)

薪資發放便利商店或零售商店的營運管理案例

店員使用什麼工具結帳？一個資料庫應用系統資料庫 ( 產品價格、庫存量、 ....) 資料庫管理系統應用程式 ( 結帳、庫存管理、訂貨、 ....)

生活有哪些零售業 ?

資料庫應用系統使用的好處與案例資料庫應用系統使用的好處與案例

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DefinitionsDefinitions Data Data (item) : stored facts concerning people, things, (item) : stored facts concerning people, things,

events, places, and objects of interestevents, places, and objects of interest StructuredStructured: such as name, address, telephone number: such as name, address, telephone number

Consisting of numbers, text, datesConsisting of numbers, text, dates Stored in Stored in tabular formtabular form

UnstructuredUnstructured (multimedia): images, video clips, documents (multimedia): images, video clips, documents InformationInformation : (complex) data processed to increase : (complex) data processed to increase

the knowledge of the persons using the data (the knowledge of the persons using the data (usersusers))

DatabaseDatabase: an organized collection of logically related : an organized collection of logically related datadata

MetadataMetadata (Data about data (Data about data 資料的描述、中介資料資料的描述、中介資料 ): ): data that describes the properties and context (data that describes the properties and context (情情境境 ) of user data) of user data

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Example

Example


Examples of Basic Definitions Data ( 資料 : 資訊的原料 )

raw facts about people, things, events, places, and objects etc.

「陳春賢」是一個華人的姓名資料「資管系」是一個大學系所的名稱資料「長庚大學」是一個大學的名稱資料「老師」是一種職業的名稱資料

Information ( 資訊 ) Complex , processed data that has value for

decision making( 資訊 : 由人、事、時、地、物等多個資料項目所組合而成 )

例如 : 「陳春賢現在是長庚大學資管系的老師」是一筆由多項資料項目組合而成的資訊

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Examples of Basic Definitions Database( 資料庫 ) 是由

一堆邏輯相關的資料和資料的描述所組成

所謂邏輯相關當我們針對一個機構的資訊需要，而建置一個資料庫時，所儲存的是與機構營運有關的資料，例如

某一大學的系所、各系所的學生、課程、老師等某一公司的產品、客戶、訂單、製造、品管、出貨、庫存等

所謂資料的描述為了要管理這些邏輯相關的資料，資料庫會儲存為了達到管理的目的而延伸出來的中介資料 (meta data)。常稱為「系統目錄」 (system catalog) ，或是「資料字典」

(data dictionary) ，如資料表的名稱、欄位名稱、欄位個數、資料筆數 6

Chapter 1 © 2013 Pearson Education© 2013 Pearson Education 7

Figure 1-1a Data in context (背景、前後文 )

Context helps users understand data

7Chapter 1 © 2013 Pearson Education© 2013 Pearson Education

Converting Data to Information

context

data records


Graphical displays turn data into useful information that managers can use for

decision making and interpretation

Figure 1-1b Summarized data


Converting Data to Information

trend


Metadata for Class Roster :Descriptions of data properties or characteristics, including data types, field sizes, allowable values, and data source 9Chapter 1 © 2013 Pearson Education© 2013 Pearson Education

Metadata Example

Datareport


Disadvantages of File Processing SystemsDisadvantages of File Processing Systems

Program-Data DependenceProgram-Data Dependence All programs maintain All programs maintain metadatametadata for each file they use for each file they use

Data redundancy (Duplication of Data)Data redundancy (Duplication of Data) Different systems/programs have separate copies of the same Different systems/programs have separate copies of the same

datadata Limited Data SharingLimited Data Sharing

No centralized (No centralized (集中化的集中化的 ) control of data) control of data Excessive Program MaintenanceExcessive Program Maintenance

80% of information system budget80% of information system budget Lengthy Development TimeLengthy Development Time

Programmers must design their own file formatsProgrammers must design their own file formats

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metadata

example


Problems with Data DependencyProblems with Data Dependency Each application programmer must maintain Each application programmer must maintain

his/her own metadatahis/her own metadata Each application program Each application program

needs to include code for the metadata of needs to include code for the metadata of each data fileeach data file

must have its own processing routines for must have its own processing routines for readingreading, , insertinginserting, , updatingupdating, and , and deletingdeleting data data

Lack of coordination and central controlLack of coordination and central control Non-standard file formatsNon-standard file formats Suppose the length of a field in the file is to Suppose the length of a field in the file is to

be changed. What to do ?be changed. What to do ?

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12Chapter 1 © 2013 Pearson Education© 2013 Pearson EducationHow a network system improves the situation ?

(Location 1) (Location 2)

Duplicate Data

D E F G

duplicate data file


Problems with Data RedundancyProblems with Data Redundancy Waste of disk space to have duplicate Waste of disk space to have duplicate

datadata Causes more maintenance headachesCauses more maintenance headaches The biggest problem: The biggest problem:

Data changes in one file could cause Data changes in one file could cause inconsistenciesinconsistencies

Compromises in Compromises in data integritydata integritySuppose some of the data are to Suppose some of the data are to

be changed. What to do ?be changed. What to do ?13


SOLUTION: The DATABASE SOLUTION: The DATABASE ApproachApproachDATABASE ApproachDATABASE ApproachA central repository A central repository (( 集中化的儲藏庫集中化的儲藏庫 )) of of

shared data via a network systemshared data via a network systemData is managed by a Data is managed by a controlling agentcontrolling agentStored in a standardized, convenient Stored in a standardized, convenient

formform

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Database Management System (DBMS)


DDataatabbase ase MManagement anagement System ystem ((DBMS))

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A software system that is used to create, manage, and provide controlled access to user databases

DBMS manages data resources like an operating system manages hardware resources

Database application systems

Order Filing System( 訂單開立系統 )

Invoicing System( 發票開立系統 )

Payroll System( 薪資管理系統 )

DBMSCentral database

Contains employee,order, inventory,

pricing, and customer data

Database management system

Database


Advantages of the Database Advantages of the Database ApproachApproach

Program-data independenceProgram-data independence Improved data sharingImproved data sharing Planned data redundancyPlanned data redundancy Enforcement of data standardsEnforcement of data standards Improved data consistencyImproved data consistency Improved data qualityImproved data quality Improved decision supportImproved decision support Increased application development Increased application development

productivityproductivity Reduced program maintenanceReduced program maintenance

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Data dependency

Traditional system


Elements of the Database Elements of the Database ApproachApproach Data models

Models capturing the nature and relationship of data Enterprise Data Model–high-level entities and relationships for the organization Project Data Model–with additional level of details for implementation, including data structures in database

Entities Describing a person, place, object, event, or concept Composed of attributes

Relationships Between entities, relating entities Usually one-to-many (1:M) or many-to-many (M:N)

Relational Databases Database technology using tables (relations) to represent entities and primary/foreign keys (PK & FK) to represent relationships

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Part of an enterprise data model

Part of a project-level data model

Figure 1-3 Comparison of enterprise and project-level data models


(Includes only the higher-level relationships of customer, order and product entities)

(Includes additional level of details)

解決顧客同名的問題

解決同一顧客下多張訂單的問題解決同一張訂單訂多項產品的問題

Entities

FK

PK

Relationships


Figure 1-5 Components of the Database Environment

人員種類

軟體種類

metadata

component details


Components of DB EnvironmentComponents of DB Environment Database Management System (DBMS) –software

for creating and managing the database Database–storehouse of the data Application Programs–software using the data CASE Tools–for designing database and applications

(Computer-Aided Software Engineering) User Interface–text and graphical displays to users Repository–centralized storehouse of metadata Data/Database Administrators–personnel

responsible for maintaining the database System Developers–personnel responsible for

designing databases and database application programs

End Users–people who use the applications and databases

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Enterprise Data ModelEnterprise Data Model First step in the database development processFirst step in the database development process Specifies scope and general content of the databasesSpecifies scope and general content of the databases Overall picture (Overall picture (整體景象整體景象 )) of organizational data at of organizational data at

high level of abstractionhigh level of abstractionContainsContains A high-level entity-relationship diagramA high-level entity-relationship diagram

((Descriptions of relationships between entities)) Business-oriented (Business-oriented (事務導向的事務導向的 ) description of entity ) description of entity

typestypes((Using business function-to-data entity matrix))

Business rulesBusiness rules(How the business operates)(How the business operates)

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FIGURE 1-6 Example : Business function-to-data entity matrix



TWO MAIN APPROACHES TO TWO MAIN APPROACHES TO DATABASE DEVELOPMENTDATABASE DEVELOPMENT PROCESSPROCESS

SDLC (SDLC (系統開發生命週期法系統開發生命週期法 )) SSystem ystem DDevelopment evelopment LLife ife CCycle (ycle (SDLCSDLC)) Detailed, well-planned development processDetailed, well-planned development process Time-consuming, but comprehensiveTime-consuming, but comprehensive Long development cycleLong development cycle

Prototyping (Prototyping (雛型開發法雛型開發法 )) One of RAD (One of RAD (RRapid apid AApplication pplication DDevelopment) methodsevelopment) methods Cursory (Cursory (粗略的粗略的 ) attempt at conceptual data modeling) attempt at conceptual data modeling Define database during development of initial Define database during development of initial

prototypeprototype Repeat implementation and maintenance activities with Repeat implementation and maintenance activities with

new prototype versions (new prototype versions (iterative development processiterative development process))

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SYSTEMS DEVELOPMENT LIFE SYSTEMS DEVELOPMENT LIFE CYCLECYCLE(SEE ALSO FIGURE 1-7)(SEE ALSO FIGURE 1-7)

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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Design

Iterative nature of system development


Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning

Purpose : : preliminary understanding of certain business needs for

database

Deliverable : : request for study

Database activity : :• enterprise data modeling (early conceptual data modeling)

SYSTEMS DEVELOPMENT LIFE CYCLESYSTEMS DEVELOPMENT LIFE CYCLE(Step : Planning)(Step : Planning)


Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

SYSTEMS DEVELOPMENT LIFE CYCLESYSTEMS DEVELOPMENT LIFE CYCLE(Step : Analysis – Conceptual Data (Step : Analysis – Conceptual Data Modeling)Modeling)

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Analysis

Purpose : thorough data requirements analysis and structuring

Deliverable : functional (功能性的 ) system specifications

Database activity : thorough and integrated conceptual data modeling (project data model : entities, relationships, PK, FK, and attributes) model


Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

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Logical Design

Purpose : Converting the conceptual schema into a logical schema

Deliverable : detailed design specifications (If relational model : tables, attributes, PKs, FKs, constraints)

Database activity : logical database design (I/O formats, transactions, reports, displays, inquiries, data integrity and security)

SYSTEMS DEVELOPMENT LIFE CYCLESYSTEMS DEVELOPMENT LIFE CYCLE(Step : Logical Database Design)(Step : Logical Database Design)


Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

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Physical Design

Purpose : develop software/hardware and organizational specifications

Deliverable : program/data structures, software/hardware purchases, organization redesigns

Database activity :physical database design (define database to certain DBMS, physical data organization, database processing programs)

SYSTEMS DEVELOPMENT LIFE CYCLESYSTEMS DEVELOPMENT LIFE CYCLE(Step : Physical Database Design & Definition)(Step : Physical Database Design & Definition)


Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

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Implementation

Purpose : programming, testing, training, installation, documenting

Deliverable : operational programs, documentation, training materials

Database activity : database implementation, including programs, documentation, installation and conversion

SYSTEMS DEVELOPMENT LIFE CYCLESYSTEMS DEVELOPMENT LIFE CYCLE(Step : Implementation)(Step : Implementation)


Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

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Maintenance

Purpose : monitor, repair, enhance

Deliverable : periodic audits (週期性稽核 )

Database activity : database maintenance, performance analysis and tuning, error corrections

SYSTEMS DEVELOPMENT LIFE CYCLESYSTEMS DEVELOPMENT LIFE CYCLE(Step : Maintenance)(Step : Maintenance)

Chapter 1 © 2013 Pearson Education© 2013 Pearson Education31

Prototyping Database Methodology(Figure 1-8)



Prototyping Database Prototyping Database MethodologyMethodology

(Figure 1-8) (Figure 1-8) (cont.)(cont.)




(Figure 1-8)(Figure 1-8) (cont.) (cont.)




(Figure 1-8)(Figure 1-8) (cont.) (cont.)



(Figure 1-8) (Figure 1-8) (cont.)(cont.)



Database SchemaDatabase Schema External SchemaExternal Schema

User ViewsUser Views Subsets of Conceptual SchemaSubsets of Conceptual Schema Can be determined from Can be determined from

business-function/data entity matricesbusiness-function/data entity matrices DBA determines schema for different usersDBA determines schema for different users

Conceptual SchemaConceptual Schema E-R models–covered in Chapters 2 and 3E-R models–covered in Chapters 2 and 3

Internal Schema Internal Schema Logical structures–covered in Chapter 4Logical structures–covered in Chapter 4 Physical structures–covered in Chapter 5Physical structures–covered in Chapter 5

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Different people have different

views of the database…these are the external

schema

The internal schema is the

underlying design and

implementation

Figure 1-9 Three-schema architecture



Evolution of Database SystemsEvolution of Database SystemsDriven by four main objectives:Driven by four main objectives:

Need for program - data independence Need for program - data independence reduced maintenancereduced maintenance

Desire to manage more complex data types Desire to manage more complex data types and structuresand structures

Ease of data access for less technical Ease of data access for less technical personnelpersonnel

Need for more powerful decision support Need for more powerful decision support platformsplatforms

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Figure 1-10a Evolution of database technologies


Figure 1-10b Database architectures


Figure 1-10b Database architectures (cont.)


Figure 1-10b Database architectures (cont.)

Data model for data warehouse


Summary of Database Summary of Database ApplicationsApplications

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Figure 1-11 Two-tier database with localarea network



Figure 1-12 Three-tiered client/server database architecture



Enterprise Database ApplicationsEnterprise Database Applications Enterprise Resource Planning (ERP)Enterprise Resource Planning (ERP)

Integrate all enterprise functions Integrate all enterprise functions (manufacturing, finance, sales, marketing, (manufacturing, finance, sales, marketing, inventory, accounting, human resources)inventory, accounting, human resources)

Data WarehouseData Warehouse Integrated decision support system derived Integrated decision support system derived

from various operational databasesfrom various operational databases

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Chapter 1 © 2013 Pearson Education CHAPTER 1: THE DATABASE ENVIRONMENT AND DEVELOPMENT PROCESS Modern…