Chapter 4 Introduction to Database Development

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Outline Context for database development Goals of database development Phases of database development CASE tools

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Information System

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Traditional Life Cycle

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Graphical Models Explicit or implicit Data model Process model Environment interaction model Emphasize data model

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Broad Goals of Database Development Develop a common vocabulary Define data meaning Ensure data quality Provide efficient implementation

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Data Quality Measures Completeness Lack of ambiguity Timeliness Correctness Consistency Reliability

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Splitting Conceptual Design

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Cross Checking Requirements

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Design Skills Soft –Qualitative –Degree of subjectivity –People-oriented Hard –Quantitative –Objective –Intensive data analysis

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Design Skills in Phases

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Features of CASE Tools Diagramming Documentation Analysis Prototyping

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. 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

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Commercial CASE Tools PowerDesigner 9 Oracle 9i Designer Visual Studio.Net Enterprise Architect ERWin ER/Studio Visible Analyst

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. ER Assistant CASE tool distributed with the textbook Customized for this textbook: supports the ERD notation used in Chapters 5 and 6 Drawing tool Diagram checking Easy to use and powerful tool

McGraw-Hill/Irwin © 2004 The McGraw-Hill Companies, Inc. All rights reserved. Summary Background for second part of the course Relationship to information systems development Broad goals Development phases CASE tool features