TM 1-1 Copyright © Addison Wesley Longman, Inc. & Dr. Chen, Business Database Systems Chapter 1 The Database Environment and Development Process Jason.

TM 1-1Copyright © Addison Wesley Longman, Inc. & Dr. Chen, Business Database Systems

Chapter 1The Database Environment and

Development Process

Jason C. H. Chen, Ph.D.

Professor of MIS

School of Business Administration

Gonzaga University

Spokane, WA 99258

[email protected]


Importance of Information

• Information (and energy) are at the core of everything around us. Our entire existence (including businesses) is a process of gathering, analyzing, understanding, and acting on the information.

• Modern organizations are said to be drowning in data but starving for information.


CAREER EARNING POTENTIAL

• Employment for Computer Systems Analysts is expected to grow much faster than average. Jobs in this area are expected to increase by 25% between 2012 and 2020. With a Bachelor's degree -- the median salary per year for this occupation is $79,680. It is expected that 127,000 new jobs will be created in this area by 2020.

•Source: U.S. Bureau of Labor Statistics.


Objectives• Define terms• Name limitations of conventional file processing• Explain advantages of databases• Identify costs and risks of databases• List components of database environment• Identify categories of database applications• Describe database system development life cycle• Explain prototyping and agile development approaches• Explain roles of individuals• Explain the three-schema architecture for databases


Definitions

• Data: Meaningful facts, text, graphics, images, sound, video segments.

• Database: An organized collection of logically related data.

• Information: Data processed to be useful in decision making.

• Metadata: Data that describes data

(Data about the data).


Reality

Meta-Data

Business and Modeling Environment

Invoice

Business

Core/Essence

Model

Data Debt, Revenue

Furniture Store

Examples:


Meta-Data

Reality

Business and Modeling Environment

Invoice

Business

Core/Essence

Model

Data Debt, Revenue

Furniture Store

Examples:


Types of Data Processing

• Two types of data processing– File-based data processing

• e.g., applications developed by Java

– Data-based data processing• e.g, applications developed by Oracle or

MS/Access)


Figure 1-2: Old file processing systems at Pine Valley Furniture

Duplicate Data

What is the main problem in the

company’s processing systems?


Disadvantages of File Processing

• Program-Data Dependence– All programs maintain metadata for each file they use

• Data Redundancy (Duplication of data)– Different systems/programs have separate copies of the same data

• Limited Data Sharing– No centralized control of data

• Lengthy Development Times– Programmers must design their own file formats

• Excessive Program Maintenance– 80% of of information systems budget


Problems with Data Dependency Each application programmer must maintain

their own data Each application program needs to include

code for the metadata of each file Each application program must have its own

processing routines for reading, inserting, updating and deleting data

Lack of coordination and central control Non-standard file formats


Problems with Data Redundancy (conti.)

• Waste of space to have duplicate data• Causes more maintenance headaches• The biggest Problem:

–When data changes in one file, could cause inconsistencies

–Compromises data integrity


SOLUTION:

• Central repository of shared data• Data is managed by a controlling agent• Stored in a standardized, convenient

form

Requires a Database Management System (DBMS)

The DATABASE Approach


Database Management System

DBMS manages data resources like an operating system manages hardware resources

DBMSDBMS Databasecontainingcentralized

shared data

Application#1

(Order Filing)

Application#2

(Invoicing Sys)

Application#3

(Payroll Sys.)

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


Database Management System

• A DBMS is a data storage and retrieval system which permits data to be stored non-redundantly while making it appear to the user as if the data is well-integrated.

• In short, a DBMS is a software package that manages a data base.


Advantages of Database Approach

• Program-Data Independence – Metadata stored in DBMS, so applications don’t need to worry

about data formats (you will know this when you learn Oracle)– Data queries/updates managed by DBMS so programs don’t

need to process data access routines– Results in: increased application development and maintenance

productivity

• Minimal Data Redundancy– Leads to increased data integrity/consistency


Advantages of Database Approach• Program-data independence• Planned data redundancy• Improved data consistency• Improved Data Sharing

– Different users get different views of the data • Improved productivity of application development• Enforcement of Standards

– All data access is done in the same way• Improved Data Quality

– Constraints, data validation rules• Improved data accessibility and responsiveness

– Use of standard data query language (SQL)• Reduced program maintenance• Improved decision support• Security, Backup/Recovery, Concurrency (not in Table 1-3)

– Disaster recovery is easier


Costs and Risks of the Database Approach

• New specialized personnel• Up-front costs:

– Installation Management Cost and Complexity– Conversion Costs

• Ongoing Costs– Requires New, Specialized Personnel– Need for Explicit Backup and Recovery

• Organizational Conflict– Old habits die hard

• Other hidden costs


Why Do We Still Learn File Processing Systems?

• File processing systems are still widely used today, especially for backing up database systems.

• Understanding the problems and limitations inherent in file processing systems can help us avoid these same problems when designing database.


Elements of the Database Approach• Data models

– Graphical system capturing nature and relationship of data– Enterprise Data Model–high-level entities and relationships for

the organization– Project Data Model–more detailed view, matching data structure

in database or data warehouse • Entities

– Noun form describing a person, place, object, event, or concept– Composed of attributes

• Relationships– Between entities– Usually one-to-many (1:M) or many-to-many (M:N)

• Relational Databases– Database technology involving tables (relations) representing

entities and primary/foreign keys representing relationships


Segment of an Enterprise Data Model

A Data Model on Customer and Order

CUSTOMER ORDER

Q1. One CUSTOMER normally places ___ ORDER?

Q2. One ORDER normally is placed by __ CUSTOMER?

How about the relationship between ORDER and PRODUCT?(see next slide)

1

M


Segment of an Enterprise Data Model

A Data Model on Customer and Order

CUSTOMER ORDER

Q1. One CUSTOMER normally places ___ ORDER?

Q2. One ORDER normally is placed by __ CUSTOMER?

How about the relationship between ORDER and PRODUCT?(see next slide)

1

M


Q3. One PRODUCT normally is contained in __ ORDER?

ORDER

ORDER_NUMBER

Customer_IDOrder_Date

Q4. One ORDER normally contains __ PRODUCT?M

M

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


Q3. One PRODUCT normally is contained in __ ORDER?

ORDER

ORDER_NUMBER

Customer_IDOrder_Date

Q4. One ORDER normally contains __ PRODUCT?M

M



(a) Segment of an Enterprise Data Model

(b) Segment of a Project-Level Data Model


Q: what are two major differences between (a) & (b)?


Figure 3Figure 1-3 Segment from Enterprise Data Model

Enterprise data model is a graphical model that shows the high-level entities for the organization and the relationship among these entities. (E/R Diagram)


Figure 3Figure 1-3 Segment from enterprise data model

One customer may place many orders, but each order is placed by a single customer

One-to-many relationship


Figure 1-3 Segment from enterprise data model

One order has many order lines; each order line is associated with a single order




One product can be in many order lines, each order line refers to a single product




Therefore, one order involves many products and one product is involved in many orders

Many-to-many relationship


Figure 1-4 Enterprise data model for Figure 1-3 segments


Figure 1-5 Components of the Database Environment


Components of the Database Environment

• CASE Tools–computer-aided software engineering• Repository–centralized storehouse of metadata• Database Management System (DBMS) –software for

managing the database• Database–storehouse of the data• Application Programs–software using the data• User Interface–text and graphical displays to users• Data/Database Administrators–personnel responsible for

maintaining the database• System Developers–personnel responsible for designing

databases and software• End Users–people who use the applications and databases

33


Evolution of Database Technologies

• Flat files - 1960s - 1980s• Hierarchical – 1970s - 1990s• Network – 1970s - 1990s• Relational – 1980s - present• Object-oriented – 1990s - present• Object-relational – 1990s - present• Data warehousing – 1980s - present


Figure 1-10a Evolution of Database Technologies


Figure 1-10b Database architecture


Figure 1-10b Database architecture


The Range of Database Applications• Personal databases• Two-tier Client/Server databases• Multitier/N Client/Server (or called web-enabled)

databases• Enterprise applications

– Enterprise resource planning (ERP) systems– Data warehousing implementations

(Web-enabled Database )

(Wide Area Network)

(WAN)

(Local Area Network)


Figure 1-11 Two-tier database with localarea network

Chapter 1


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

Chapter 1

TM 1-41Copyright © Addison Wesley Longman, Inc. & Dr. Chen, Business Database Systems41

Muti/N-tier: Web-Enabled Databases

• Web applications requiring databases– Customer relationship management (CRM)– Business-to-consumer (B2C)– Electronic data interchange (EDI)– Private intranets– XML-defined Web services


Enterprise Applications

• Enterprise Resource Planning (ERP)– Integrate all enterprise functions (manufacturing,

finance, sales, marketing, inventory, accounting, human resources)

• Data Warehousing implementation– Integrated decision support system derived from

various operational databases


Break ! (Ch. 1)Exercise #1 (p.44)

Homework:1. Complete chapter1 quiz by Sunday evening.2. HW#12 (a) only (homework assignment - high-level (no attributes) - draw by Visio clearly - turn in a hardcopy next class


Be Prepared for ...


Discuss HW

• HW#12 (a)• Volunteer?


Enterprise Data Model

• Enterprise data modeling is the first step in database development, in which the scope and general contents of organizational databases are specified.

• Descriptions of entity types• Relationships between entities• Business rules

Enterprise data model is a graphical model that shows the high-level entities for the organization and the relationship among these entities. (E/R Diagram)

Q: Is ER/M a top-down or bottom-up approach?


Steps in the Database Development Process

• Enterprise Modeling• Conceptual Data Modeling

– Cuts across Project Initiation and Planning & Analysis phases of SDLC

• Logical Database Design (E/R)• Physical Database Design and Creation • Database Implementation• Database Maintenance


Life Cycle Phases of DA and DBA (Ch.11)

Database Planning

Database Analysis

Database Implementation

Database Design

Operations and Maintenance

Growth and Change


Two Approaches to Database and IS Development

• SDLC– System Development Life Cycle– Detailed, well-planned (and structured) development

process– Time-consuming, but comprehensive– Long development cycle

• Prototyping– Rapid application development (RAD)– Cursory attempt at conceptual data modeling– Define database during development of initial prototype– Repeat implementation and maintenance activities with new

prototype versions– Tool: Oracle Designer


Database Design

• Systems Development Life Cycle (SDLC)• Entity-relationship model (E-R model)• Normalization


Systems Development Life Cycle

Systems ImplementationProduct:

Operational System

Systems ImplementationProduct:

Operational System

Systems Investigation(Definition) Product:

Feasibility Study

Systems Investigation(Definition) Product:

Feasibility Study

Systems AnalysisProduct:

Functional Requirements

Systems AnalysisProduct:

Functional Requirements

Systems DesignProduct:

System Specifications

Systems DesignProduct:

System Specifications

Systems MaintenanceProduct:

Improved System

Systems MaintenanceProduct:

Improved System

Understand theBusinessProblem orOpportunity

Develop anInformationSystemSolution

Implementthe InformationSystemSolution


Prototyping

• Prototpying is one of the most popular rapid application development (RAD) methods.

• It is an iterative process of system development in which requirements are converted to a working system that is continually revised through close work between analysts and users.

A prototype is a small, but working system that contains only those important (not complete) features.


Systems Development Life Cycle (see also Figure 1-7)

Project Identification and Selection

Project Initiation and Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design


Systems Development Life Cycle (see also Figure 1.7)



Analysis

Physical Design

Implementation

Maintenance

Logical Design

Purpose --preliminary understandingDeliverable –request for project

Database activity – enterprise modeling





Analysis

Physical Design

Implementation

Maintenance

Logical Design

Purpose – state business situation and solutionDeliverable – request for analysis

Database activity – conceptual data modeling





Analysis

Physical Design

Implementation

Maintenance

Logical Design

Purpose –thorough analysisDeliverable – functional system specifications

Database activity – conceptual data modeling





Analysis

Physical Design

Implementation

Maintenance

Logical Design

Purpose –information requirements structureDeliverable – detailed design specifications

Database activity – logical database design





Analysis

Physical Design

Implementation

Maintenance

Logical Design

Purpose –develop technology specsDeliverable – program/data structures, technology purchases, organization redesigns

Database activity – physical database design





Analysis

Physical Design

Implementation

Maintenance

Logical Design

Purpose –programming, testing, training, installation, documentingDeliverable – operational programs, documentation, training materials

Database activity – database implementation





Analysis

Physical Design

Implementation

Maintenance

Logical Design

Purpose –monitor, repair, enhanceDeliverable – periodic audits

Database activity – database maintenance


Figure 1-7: Database development activities during the systems development life cycle (SDLC)



Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning (Enterprise modeling)

Conceptual data modeling

Upper CASE tool

(Front-end)

Lower CASE tool(Back-end)

Integrate database viewsand perform normalization

Growth and Change


62

Figure 1-8The prototyping methodology and database development process


63

Figure 1-8 The prototyping methodology and database development process (cont.)


64





66



Managing Projects

• Project–a planned undertaking of related activities to reach an objective that has a beginning and an end

• Initiated and planned in planning stage of SDLC

• Executed during analysis, design, and implementation

• Closed at the end of implementation

67


Managing Projects: People Involved• Project is a planned undertaking of related activities to reach an

objective that has a beginning and an end• People involved:

– Business analysts – work with management and users to analyze business– Systems analysts - business situation and IS needs– Database analysts and modelers - requirements and design for the

database component of the IS– Users - assessment of their information needs and monitor the developed

system meet their needs– Programmers – design and write computer programs– Database architects – establish standards– Database and data administrators - ensure database consistency, integrity

and provide consulting, training etc..– Project managers – oversees assigned projects– Other technical experts - network administrators, testers, technical writers


The Technology Level of Models

• Conceptual models focus on the underlying content of an information system with no assumptions about technology

• Logical models assume a general class of technology (H/S W independent) – a relational database

• Internal models assume specific technologies – for example, an Oracle database engine


Database Schema• External Schema (during the analysis and logical design phases)

– User Views– Subsets of Conceptual Schema– Can be determined from business-function/data entity

matrices– DBA determines schema for different users– This is part of people-management in databases

• Conceptual Schema– ER models (during the analysis phase)– covered in

chapters 2 and 3• Internal Schema

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


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


Figure 1-9: Three-schema database architecture

ExternalSchema

InternalSchema

Meta-data/Repository/

D.D.

E/R, OO …

Relations

Database

Ch. 4

Ch. 2,3,4

Ch. 5

N

Levels of database schemas

• Different schemas are presented to different users

External level

internal to logical mapping

logical to external mappings

disk

Internal Schema Internal level

External View 1 External View 2 External View 3

Logical Schema Logical level

N


Exercise/Homework

Homework

(1) #17 ; p.45; three views with E/R

- Statement View

- Deposit View

- Conceptual View (an integrated view the

above two views)

Hint: account/customer is one of common entity(Draw by Visio/Word, turn in hardcopy, due next class)

(2) Online Quiz#1 (due date, midnight Sunday)


FIGURE 1-15 (a): Preliminary data model for Home Office product line marketing support system


FIGURE 1-15: Project data model for Home Office product line marketing support system



TM 1-1 Copyright © Addison Wesley Longman, Inc. & Dr. Chen, Business Database Systems Chapter 1 The Database Environment and Development Process Jason.

Documents

data data

related data

companys processing

data redundancy duplicatio

databases slide

old file processing

msaccess slide

computer systems analysts