Data Flow diagrams are widely used in software engineering, information systems, and data base design. They represent processes and flows of data between processes. They have three types of symbols. Namely, interfaces, repositories, and processes. Interfaces represent the "boundaries" of the system. Repositories represent information stored in the system. Processes represent agents (for example SW modules) that elaborate information. Interfaces, processes, and repositories are usually represented as squares, smoothed squares, and right-open rectangles, respectively. Connections between symbols are usually "directed". The arrow along a connection illustrates the direction of the flow of information.

Speaking in terms of graph properties, Data Flow diagrams are directed graphs.

We suggest to represent Data Flow diagrams with orthogonal drawings, i.e., drawings in which the connections between symbols consist of horizontal and vertical segments only.

The following figure shows an example of Data Flow diagram constructed with GDT.

GAPI tutorial on orthogonal drawings and BLAG tutorial on orthogonal drawings provide a comprehensive guide on how to use GDT to construct these widely used drawings.

 


Last update : July 31, 2002
Website design by INTEGRA Sistemi, www.IntegraSistemi.it