Chapter 1:Chapter 1:The Database Environment and The Database Environment and Development ProcessDevelopment Process

Essentials of Database Management

Jeffrey A. Hoffer, Heikki Topi, V. Ramesh

Copyright © 2014 Pearson Education, Inc. 1

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Basic DB Terms

Data: Meaningful facts, text, graphics, images, sound, video segments A collection of individual responses from a marketing

research

Information: Data processed to be useful in decision making Pattern of geographical buying habit based on analysis of a

marketing research

Metadata: Data that describes data

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Data in Context

Large volume of facts, difficult to interpret / make decisions

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Information

Useful for decision making / interpretation

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Metadata

Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and documentation (Data Dictionary)

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Universal Database Systems

DBMSDBMS Databasecontainingcentralized

shared data

Application#1

Application#2

Application#3

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Database Systems

Collection of electronic data Central repository of shared data Stored in a standardized, convenient form. Requires a Database Management System (DBMS)

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Type of DB Models

File processing system (traditional) Hierarchical Network Relational Object-relational

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Relational Database

A relational database is a collection of tables that are related to one another based on a common field.

A common field is called a primary key(s). unique identifier in data model

When the primary key of one table is represented in a second table to form a relationship, it is called a foreign key.

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Relational Database

A schematic diagram of a relational database (a) and a sample part of a relational database showing different tables (b)

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Relating Tables Using a Common Field

The primary key in the Employer table (EmployerID) is the common field that relates this table to the Position table.

PositionID is the primary key in the Position table. The EmployerID field is a foreign key in this table.

Primary keys can only have one occurrence in a table. Foreign keys may have multiple occurrences.

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Relational Database

Advantages Easier database design, implementation,

management, and use Ad hoc query capability with SQL Powerful database management system

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DATABASE MODEL PRODUCT VENDOR HARDWAREHierarchical Focus Information Builders International Mainframe/PC

IMS IBM MainframeRamis Online Software International Mainframe

Network ADABAS Software AG of North America MainframeImage Hewlett-Packard Mainframe

Relational Access Microsoft PCDB2 IBM MainframedBASE V Borland International PCEDA/SQL Information Builders International PCFoxPro Microsoft PCIngres Ask Group PCNOMAD Must Software International Mainframe/PCOracle Oracle Mainframe/PCParadox Borland International PCRbase Microrim PCSQL/DS IBM MainframeSQL Server Microsoft PCSybase Sybase PC

Object-Relational ObjectStore Object Design PCUniversalServer

Informix PC

Illustra Informix PC

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Database Applications

Personal Database – standalone desktop database

Workgroup Database – local area network (<25 users)

Department Database – local area network (25-100 users)

Enterprise Database – wide-area network (hundreds or thousands of users)

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Data Warehouse

Collection of historic… NOT current data…

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Data Mining

• Help to find hidden patterns and relationships in large databases to predict future behavior

– “If a house is purchased, then new refrigerator will be purchased within two weeks 65% of the time.”

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Components of the DB Environment

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Components of the DB Environment

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

database Database – storage of the data Application Programs – software using the data User Interface – text and graphical displays to users Database Administrators (DBA) – personnel responsible for

maintaining the database System Developers – personnel responsible for designing databases

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

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Database Development Process

Feasibility Study of Project

Requirement Analysis

Conceptual Design

Physical Design

Implementation

Maintenance

Logical Design

Purpose – preliminary understanding

Deliverable –request for project

- Is the project worth looking at ?- Is the DB system worth building?

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Feasibility Study of Project

Requirement Analysis

Conceptual Design

Physical Design

Implementation

Maintenance

Logical Design

Purpose – state business situation and possible solutionDeliverable –decomposed requirements

Database Development Process

• What do users need and want from the new system?• What the new system must do

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Feasibility Study of Project

Requirement Analysis

Conceptual Design

Physical Design

Implementation

Maintenance

Logical Design

Purpose –thorough analysis

Deliverable – conceptual data model

Database Development Process

conceptual data model- next slide

- example model from the web page

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Conceptual Data Model

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Feasibility Study of Project

Requirement Analysis

Conceptual Design

Physical Design

Implementation

Maintenance

Logical Design

Purpose –information requirements structure

Deliverable – logical database design

Database Development Process

1. Hierarchical DB

2. Network DB

3. Relational DB

4. Object Oriented

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Feasibility Study of Project

Requirement Analysis

Conceptual Design

Physical Design

Implementation

Maintenance

Logical Design

Purpose –develop technology specsDeliverable – program/data structures, DB technology purchases…

Database Development Process

• Define physical organization of data

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Feasibility Study of Project

Requirement Analysis

Conceptual Design

Physical Design

Implementation

Maintenance

Logical Design

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

Database Development Process

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Feasibility Study of Project

Requirement Analysis

Conceptual Design

Physical Design

Implementation

Maintenance

Logical Design

Purpose –monitor, repair, enhanceDeliverable – periodic audits

Database Development Process

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DB Development Schedule

Gantt Chart shows time estimates of tasks

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PERT Chart shows dependencies between tasks

DB Development Schedule …

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Incremental Commitment in DB Development

Project is reviewed at the end of each development phase Re-justify the process under the light of new requirements

and available resources Renew commitment of stakeholders Continue / Revise Scope / Cancel