Transcript ppt - Spatial Database Group

Chapter 2
Introduction to Database
Development
Database Design, Application Development, and
Administration, 5th Edition
Copyright © 2011 by Michael V. Mannino All rights reserved.
Outline
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Context for database development
Goals of database development
Phases of database development
CASE tools
Chapter 2: Introduction to Database Development
Slide 2
Information System
INPUTS
Loan Applications
OUTPUTS
PROCESSES
ENVIRONMENT
Payments
Student Loan
Processing
System
Delinquency
Notices
ENVIRONMENT
Statements
Cash
Disbursements
Status
Changes
DATABASE
Chapter 2: Introduction to Database Development
Slide 3
Traditional Life Cycle
Preliminary
Investigation
Problem Statement,
Feasibility Study
Systems
Analysis
System Requirements
Feedback
Systems
Design
Feedback
Design Specifications
Systems
Implementation
Operational
System
Maintenance
Feedback
Chapter 2: Introduction to Database Development
Slide 4
Development Alternatives
 Difficulties
 Operational system is produced late
 Rush to begin implementation
 Requirements are difficult to capture
 Alternative methodologies
 Spiral approaches
 Rapid application development
 Prototypes may reduce risk
Chapter 2: Introduction to Database Development
Slide 5
Graphical Models
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Explicit or implicit
Data model
Process model
Environment interaction model
Emphasize data model
Chapter 2: Introduction to Database Development
Slide 6
Broad Goals of Database
Development
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Develop a common vocabulary
Define data meaning
Ensure data quality
Provide efficient implementation
Chapter 2: Introduction to Database Development
Slide 7
Develop a Common
Vocabulary
 Diverse groups of users
 Difficult to obtain acceptance of a common
vocabulary
 Compromise to find least objectionable
solution
 Unify organization by establishing a
common vocabulary
Chapter 2: Introduction to Database Development
Slide 8
Define Meaning of Data
 Business rules support organizational
policies
 Restrictiveness of business rules
 Too restrictive: reject valid business
interactions
 Too loose: allow erroneous business
interactions
 Exceptions allow flexibility
Chapter 2: Introduction to Database Development
Slide 9
Data Quality
 Poor data quality leads to poor decision
making
 Difficult customer communication
 Inventory shortages
 Cost-benefit tradeoff to achieve desired
level of data quality
 Long-term effects of poor data quality
Chapter 2: Introduction to Database Development
Slide 10
Data Quality Measures
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Completeness
Lack of ambiguity
Timeliness
Correctness
Consistency
Reliability
Chapter 2: Introduction to Database Development
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Efficient Implementation
 Supersedes other goals
 Optimization problem
 Maximize performance
 Subject to constraints of data quality, data
meaning, and resource usage
 Difficult problem:
 Number of choices
 Relationships among choices
 DBMS specific
Chapter 2: Introduction to Database Development
Slide 12
Database Development Phases
Data
requirements
Conceptual Data
Modeling
ERD
Logical Database
Design
Tables
Distributed Database
Design
Distribution Schema
Physical Database
Design
Chapter 2: Introduction to Database Development
Internal Schema,
Populated DB
Slide 13
Conceptual Data Modeling
 Information content of the database
 Entity relationship diagram (ERD) showing
entity types and relationships
 Historically, DBMSs did not support many
constraints.
 Diverse formats for database requirements
Chapter 2: Introduction to Database Development
Slide 14
Logical Database Design
 Refine conceptual design
 Convert ERD to table design
 Analyze design for excessive
redundancies
 Normalization: tool to reason about
redundancies
 Add constraints to enforce business rules
Chapter 2: Introduction to Database Development
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Distributed Database Design
 Location of data and processing
 Performance orientation, not information
content orientation
 Allocate subsets of database to different
sites
 Replicate subsets of database to improve
availability
Chapter 2: Introduction to Database Development
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Physical Database Design
 Performed at each independent database
site
 Minimize response time without
consuming excessive resources
 Tradeoffs: retrieval versus update
 Flexible designs versus specialized
designs
 Decisions: indexes, data placement
Chapter 2: Introduction to Database Development
Slide 17
Splitting Conceptual Design
Conceptual Data Modeling
Data Requirements
View Design
View ERDs
View Integration
Entity Relationship Diagrams
Chapter 2: Introduction to Database Development
Slide 18
Cross Checking Requirements
System
Requirements
Data Requirements
Database
Development
Application Requirements
Cross
Checking
ERDs, Table Design,
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Application
Development
Process Models,
Interaction Models,
Prototypes
Operational
Applications
Operational
Database
Operational
System
Chapter 2: Introduction to Database Development
Slide 19
Design Skills
 Soft
 Qualitative
 Degree of subjectivity
 People-oriented
 Hard
 Quantitative
 Objective
 Intensive data analysis
Chapter 2: Introduction to Database Development
Slide 20
Design Skills in Phases
Data Requirements
Conceptual Data
Modeling
Design Skills
Soft
Entity Relationship
Diagrams
Logical Database
Design
Relational Database
Tables
Distributed
Database Design
Distribution Schema
Physical
Database Design
Internal Schema, Populated Database
Hard
Chapter 2: Introduction to Database Development
Slide 21
Features of CASE Tools
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Diagramming
Documentation
Analysis
Prototyping
Chapter 2: Introduction to Database Development
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Classification of CASE Tools
 Front-end vs. Back-end
 Front-end emphasize data modeling and
logical analysis
 Back-end emphasize code generation and
physical design
 DBMS dependent vs. DBMS independent
Chapter 2: Introduction to Database Development
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Commercial CASE Tools
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PowerDesigner
Oracle SQL Developer Data Modeler
Visual Premium
CA ERWin Modeling Family
ER/Studio Enterprise
Visible Analyst
Aqua Data Studio
Chapter 2: Introduction to Database Development
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Visio Professional
 Entry level version of Visual Premium
 Drawing tools
 Stencils for database diagrams
 Glue feature to retain connections
 Data dictionary support
 Analysis tools
 Diagram layout
 Error checking
 Reverse engineering
Chapter 2: Introduction to Database Development
Slide 25
Visio Professional Templates
Chapter 2: Introduction to Database Development
Slide 26
Entity Relationship Model in
Visio Professional
Chapter 2: Introduction to Database Development
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Property Windows in Visio
Professional
Chapter 2: Introduction to Database Development
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Summary
 Background for Chapters 5 to 8
 Relationship to information systems
development
 Broad goals
 Development phases
 CASE tool features
Chapter 2: Introduction to Database Development
Slide 29