Database Design, Application Development, and Administration, 5 th Edition Copyright © 2011 by Michael V. Mannino All rights reserved. Chapter 2 Introduction to Database Development

Slide 2Chapter 2: Introduction to Database Development Outline  Context for database development  Goals of database development  Phases of database development  CASE tools

Slide 3Chapter 2: Introduction to Database Development Information System

Slide 4Chapter 2: Introduction to Database Development Traditional Life Cycle

Slide 5Chapter 2: Introduction to Database Development 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

Slide 6Chapter 2: Introduction to Database Development Graphical Models  Explicit or implicit  Data model  Process model  Environment interaction model  Emphasize data model

Slide 7Chapter 2: Introduction to Database Development Broad Goals of Database Development  Develop a common vocabulary  Define data meaning  Ensure data quality  Provide efficient implementation

Slide 8Chapter 2: Introduction to Database Development 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

Slide 9Chapter 2: Introduction to Database Development 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

Slide 10Chapter 2: Introduction to Database Development 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

Slide 11Chapter 2: Introduction to Database Development Data Quality Measures  Completeness  Lack of ambiguity  Timeliness  Correctness  Consistency  Reliability

Slide 12Chapter 2: Introduction to Database Development 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

Slide 13Chapter 2: Introduction to Database Development Database Development Phases Conceptual Data Modeling Logical Database Design Distributed Database Design Physical Database Design ERD Tables Distribution Schema Internal Schema, Populated DB Data requirements

Slide 14Chapter 2: Introduction to Database Development 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

Slide 15Chapter 2: Introduction to Database Development 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

Slide 16Chapter 2: Introduction to Database Development 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

Slide 17Chapter 2: Introduction to Database Development 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

Slide 18Chapter 2: Introduction to Database Development Splitting Conceptual Design

Slide 19Chapter 2: Introduction to Database Development Cross Checking Requirements

Slide 20Chapter 2: Introduction to Database Development Design Skills  Soft  Qualitative  Degree of subjectivity  People-oriented  Hard  Quantitative  Objective  Intensive data analysis

Slide 21Chapter 2: Introduction to Database Development Design Skills in Phases

Slide 22Chapter 2: Introduction to Database Development Features of CASE Tools  Diagramming  Documentation  Analysis  Prototyping

Slide 23Chapter 2: Introduction to Database Development 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

Slide 24Chapter 2: Introduction to Database Development Commercial CASE Tools  PowerDesigner  Oracle SQL Developer Data Modeler  Visual Premium  CA ERWin Modeling Family  ER/Studio Enterprise  Visible Analyst  Aqua Data Studio

Slide 25Chapter 2: Introduction to Database Development 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

Slide 26Chapter 2: Introduction to Database Development Visio Professional Templates

Slide 27Chapter 2: Introduction to Database Development Entity Relationship Model in Visio Professional

Slide 28Chapter 2: Introduction to Database Development Property Windows in Visio Professional

Slide 29Chapter 2: Introduction to Database Development Summary  Background for Chapters 5 to 8  Relationship to information systems development  Broad goals  Development phases  CASE tool features