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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
2
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