Structured analysis

In software engineering, structured analysis (SA) and structured design (SD) are methods for analyzing business requirements and developing specifications for converting practices into computer programs, hardware configurations, and related manual procedures. In software engineering, structured analysis (SA) and structured design (SD) are methods for analyzing business requirements and developing specifications for converting practices into computer programs, hardware configurations, and related manual procedures. Structured analysis and design techniques are fundamental tools of systems analysis. They developed from classical systems analysis of the 1960s and 1970s. Structured analysis became popular in the 1980s and is still in use today. Structured analysis consists of interpreting the system concept (or real world situations) into data and control terminology represented by data flow diagrams. The flow of data and control from bubble to the data store to bubble can be difficult to track and the number of bubbles can increase. One approach is to first define events from the outside world that require the system to react, then assign a bubble to that event. Bubbles that need to interact are then connected until the system is defined. Bubbles are usually grouped into higher level bubbles to decrease complexity. Data dictionaries are needed to describe the data and command flows, and a process specification is needed to capture the transaction/transformation information. SA and SD are displayed with structure charts, data flow diagrams and data model diagrams, of which there were many variations, including those developed by Tom DeMarco, Ken Orr, Larry Constantine, Vaughn Frick, Ed Yourdon, Steven Ward, Peter Chen, and others. These techniques were combined in various published system development methodologies, including structured systems analysis and design method, profitable information by design (PRIDE), Nastec structured analysis & design, SDM/70 and the Spectrum structured system development methodology. Structured analysis is part of a series of structured methods that 'represent a collection of analysis, design, and programming techniques that were developed in response to the problems facing the software world from the 1960s to the 1980s. In this timeframe most commercial programming was done in Cobol and Fortran, then C and BASIC. There was little guidance on 'good' design and programming techniques, and there were no standard techniques for documenting requirements and designs. Systems were getting larger and more complex, and the information system development became harder and harder to do so.' As a way to help manage large and complex software, the following structured methods emerged since the end of the 1960s : According to Hay (1999) 'information engineering was a logical extension of the structured techniques that were developed during the 1970's. Structured programming led to structured design, which in turn led to structured systems analysis. These techniques were characterized by their use of diagrams: structure charts for structured design, and data flow diagrams for structured analysis, both to aid in communication between users and developers, and to improve the analyst's and the designer's discipline. During the 1980's, tools began to appear which both automated the drawing of the diagrams, and kept track of the things drawn in a data dictionary'. After the example of computer-aided design and computer-aided manufacturing (CAD/CAM), the use of these tools was named computer-aided software engineering (CASE).