STRUCTURED ANALYSIS AND SYSTEM SPECIFICATION

Transcription

1 r STRUCTURED ANALYSIS AND SYSTEM SPECIFICATION by Tom DeMarco Foreword by P.J. Plauger =3p YOURDDN PRESS =fm P T R PRENTICE HALL Englewood Cliffs, NJ 07632

2 PAGE PARTI: BASIC CONCEPTS 1. The Meaning of Structured Analysis What is analysis? Problems of analysis The user-analyst relationship What is Structured Analysis? Conduct of the analysis phase The classical project life cycle The modern life cycle The effect of Structured Analysis on the life cycle Procedures of Structured Analysis Characteristics of the Structured Specification Political effects of Structured Analysis Questions and answers The Tools of Structured Analysis A sample situation A Data Flow Diagram example A Data Dictionary example A Structured English example A Decision Table example A Decision Tree example 44 PART 2: FUNCTIONAL DECOMPOSITION 4. Data Flow Diagrams What is a Data Flow Diagram? A Data Flow Diagram by any other name DFD characteristics inversion of viewpoint 48

3 viii CONTENTS 5. Data Flow Diagram conventions Data Flow Diagram elements Procedural annotation of DFD's The Lump Law Guidelines for drawing Data Flow Diagrams Identifying net inputs and outputs Filling in the DFD body Labeling data flows Labeling processes Documenting the steady state Omitting trivial error-handling details Portraying data flow and not control flow Starting over Leveled Data Flow Diagrams Top-down analysis the concept of leveling Elements of a leveled DFD set Leveling conventions Bottom-level considerations Advantages of leveled Data Flow Diagrams Answers to the leveled DFD Guessing Game A Case Study in Structured Analysis Background for the case study Welcome to the project context of analysis The top level Intermezzo: What's going on here? The lower levels Summary Postscript Evaluation and Refinement of Data Flow Diagrams Tests for correctness Tests for usefulness Starting over Data Flow Diagrams for System Specification The man-machine dialogue The integrated top-level approach Problems and potential problems 120

4 ix PART 3: DATA DICTIONARY 11. The analysis phase Data Dictionary The uses of Data Dictionary Correlating Data Dictionary to the DFD's Implementation considerations Definitions in the Data Dictionary Characteristics of a definition Definition conventions Redundancy in DD definitions Self-defining terms Treatment of aliases What's in a name? Sample entries by class Logical Data Structures Data base considerations Data Structure Diagrams (DSD's) Uses of the Data Structure Diagram Data Dictionary Implementation Automated Data Dictionary Manual Data Dictionary Hybrid Data Dictionary Librarian's role in Data Dictionary Questions about Data Dictionary 164 PART 4: PROCESS SPECIFICATION 15. Description of Primitives Specification goals Classical specification writing methods Alternative means of specification Structured English Definition of Structured English An example The logical constructs of Structured English The vocabulary of Structured English Structured English styles The balance sheet on Structured English Gaining user acceptance 212

5 17. Alternatives for Process Specification 17.1 When to use a Decision Table 17.2 Getting started 17.3 Deriving the condition matrix 17.4 Combining Decision Tables and Structured English 17.5 Selling Decision Tables to the user 17.6 Decision Trees 17.7 A procedural note 17.8 Questions and answers PART 5: SYSTEM MODELING 18. Use of System Models 18.1 Logical and physical DFD characteristics 18.2 Charter for Change 18.3 Deriving the Target Document 19. Building a Logical Model of the Current System 19.1 Use of expanded Data Flow Diagrams 19.2 Deriving logical file equivalents 19.3 Brute-force logical replacement 19.4 Logical DFD walkthroughs 20. Building a Logical Model of a Future System 20.1 The Domain of Change 20.2 Partitioning the Domain of Change 20.3 Testing the new logical specification 21. Physical Models 21.1 Establishing options 21.2 Adding configuration-dependent features 21.3 Selecting an option 22. Packaging the Structured Specification 22.1 Filling in deferred details 22.2 Presentation of key interfaces 22.3 A guide to the Structured Specification 22.4 Supplementary and supporting material

6 PART 6: STRUCTURED ANALYSIS FOR A FUTURE SYSTEM 23. Looking Ahead to the Later Project Phases Analyst roles during design and implementation Bridging the gap from analysis to design User roles during the later phases Maintaining the Structured Specification Goals for specification maintenance The concept of the specification increment Specification maintenance procedures The myth of Change Control Transition into the Design Phase Goals for design Structured Design Implementing Structured Designs Acceptance Testing Derivation of normal path tests Derivation of exception path tests Transient state tests Performance tests Special tests Test packaging Heuristics for Estimating The empirically derived estimate Empirical productivity data Estimating rules 336 GLOSSARY 341 BIBLIOGRAPHY 347 INDEX 349