Editing Data-flow diagram (section)

==History==
The DFD notation draws on [[graph theory]], originally used in operational research to model workflow in organizations, and in computer science to model the flow of inputs and outputs across computations.<ref>{{Cite journal |last1=Martin |first1=David |last2=Estrin |first2=Gerald |date=1967-04-01 |title=Models of Computations and Systems—Evaluation of Vertex Probabilities in Graph Models of Computations |url=https://dl.acm.org/doi/10.1145/321386.321391 |journal=Journal of the ACM |volume=14 |issue=2 |pages=281–299 |doi=10.1145/321386.321391 |issn=0004-5411}}</ref><ref name=":2" /> DFD originated from the [[structured analysis and design technique]] methodology in the middle of the 1970s.<ref name=":2">{{Cite book |last1=Yourdon |first1=Edward |title=Structured Design |last2=Constantine |first2=Larry L. |date=1975 |publisher=Yourdon Inc. |location=New York |pages=54–55 |oclc=1036882595}}</ref> It was first proposed by Larry Constantine,<ref>{{Cite book |last=Bergland |first=G. D. |chapter=Structured Design Methodologies |date=1978-06-19 |title=15th Design Automation Conference |chapter-url=https://dl.acm.org/doi/10.5555/800095.803131 |location=Las Vegas, Nevada, USA |publisher=IEEE Press |pages=475–493 |doi=10.1109/DAC.1978.1585214 }}</ref> and popularized by [[Edward Yourdon]], Tom DeMarco,<ref name=":3">{{Cite book |last=DeMarco |first=Tom |title=Structured analysis and system specification |date=1979 |publisher=Prentice-Hall |isbn=978-0-13-854380-8 |series=Prentice-Hall software series |location=Englewood Cliffs, N.J}}</ref> Chris Gane and Trish Sarson,<ref name=":4">{{Cite book |last1=Gane |first1=Chris |title=Structured systems analysis: tools and techniques |last2=Sarson |first2=Trish |date=1979 |publisher=Prentice-Hall |isbn=978-0-13-854547-5 |series=Prentice-Hall software series |location=Englewood Cliffs, N.J}}</ref><ref name=":1">{{Cite book|last=Yourdon|first=Edward|title=Proceedings of the May 19-22, 1975, national computer conference and exposition on - AFIPS '75 |chapter=Structured programming and structured design as art forms |date=1975|pages=277|doi=10.1145/1499949.1499997|s2cid=36802486|doi-access=free}}</ref> who enriched the diagramming technique with different notations, data dictionary practices<ref name=":3" /> and guidance for the hierarchical decomposition of processes.<ref name=":4" />    

The primary aim of data-flow diagrams  in the context of structured design was to build complex modular systems, rationalizing the interdependencies across different modules.<ref name=":2" />  Data-flow diagrams (DFD) quickly became a popular way to visualize the major steps and data involved in software-system processes. DFDs were usually used to show data flow in a computer system, although they could in theory as well be applied to [[business process modeling]].<ref>{{Cite journal |last1=Tangkawarow |first1=I R H T |last2=Waworuntu |first2=J |date=April 2016 |title=A Comparative of business process modelling techniques |journal=IOP Conference Series: Materials Science and Engineering |volume=128 |issue=1 |pages=012010 |doi=10.1088/1757-899X/128/1/012010 |issn=1757-8981|doi-access=free |bibcode=2016MS&E..128a2010T }}</ref> DFDs were useful to document the major data flows or to explore a new high-level design in terms of data flow.<ref>{{Cite book|title=Applying UML and patterns : an introduction to object-oriented analysis and design and iterative development|first=Craig|last=Larman|date=2012|publisher=Pearson|isbn=978-8177589795|edition= 3rd|location=New Delhi|oclc=816555477}}</ref>