Menu

Structured Methods

Introduction

Structured methods are used to generate models in an organized manner. These methods find their applications in the requirements elucidation and analysis phase of the software development process. They provide a core framework that can be successfully applied in developing detailed and specifically large models.

Structured methods consist of a set of processes and rules/regulations adhering to which sophisticated models are developed. These methods also produce standard documents for the system.

They encompass several CASE tools (Computer-Aided Software Engineering tools) which can be effectively used for:

  • Modifying existing models

  • Developing code

  • Generating reports

  • Validating available models to some extent

Components of CASE Tools

A brief illustration of these CASE tools is given below:

1. Code Generators

  • Automatically generate code or code format based on information available in the central information storage.

2. Import/Export Facilities

  • Allows the transfer of data to and from the central storage and external sources.

3. Form Definition Tools

  • Define formats or specifications for developing reports or forms, and for structuring data on the screen.

4. Reports Definition and Generation Tools

  • Automatically generate documents using data from the central storage.

5. Data Dictionary

  • Stores large volumes of system-related entity information in an organized way.

6. Central Information Storage Query Language

  • Allows users to retrieve design information stored in central storage using queries.

7. Diagram Editors

  • Help generate various models (behavioral, object-data models, etc.) and store related information in the central storage.

8. Design Analysis and Checking Tools

  • Used to evaluate reports and documentation, and to identify errors.

Models Used for Structured Analysis

Structured methods use the following modeling approaches:

1. Data Model

  • Used as a data dictionary in structural analysis.

  • Acts as a centralized repository of data and objects.

2. Entity-Relation Model

  • Represented using an ER diagram.

  • Helps understand relationship types and nature among entities.

3. Data Modeling

  • Deployed using data structure diagrams.

  • Represents how data is stored in terms of structure and attributes.

4. Data Flow

  • Represented using a Data Flow Diagram (DFD).

  • Shows how data flows through various functions of the system.

5. State Transition Model

  • Represented as process flow charts.

  • Shows how system functions behave under the influence of external stimuli.

6. System Model

  • Visualized using system flow diagrams.

  • Describes system context, position, and interfaces.

7. Modeling Language

  • Provides diagramming notations for representing entities, process flows, storage, decisions, and visual models.