Talk:Data-flow diagram

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Clean up

I started trying to clean up the article -- I think it was a rough translation from German.

Nope, this is just me trying to convey the information that i know is correct, but am not allowed to just copy and paste... Beta_M ^talk, |^contrib (Ë-Mail)

I think it's quite good, it just needs some examples that my school might be able to provide.(Contact Rossmoyne Senior High School in Perth Australia) Rajeshn Pryani

Example might be needed

Maybe someone should give an example where some c code (or code in another language)can be transformed into a DFD

Add example for DFD

C Code is logical and can easily be converted to a logic flow. Data Flow is the movement of data between entities and the processes that are used to accomplish that. Think of each process as a black box. The inputs are the flows into the process and the outputs are the flows out of the process. Eventually the flows arrive at an entity (Person, Department, Customer, System, etc...) —Preceding unsigned comment added by 63.226.136.254 (talk) 13:05, 23 July 2009 (UTC)[reply]

Removed

Removed *Chapter from a book by Edward Yourdon Because it is a broken link.

Attempt to improve the page

I've attempted to start improving this page and work towards removing the clean-up tag. Any suggestions or additions would be much appreciated. Ranglin 06:19, 4 November 2005 (UTC)[reply]

some information about DFD Documentation should be useful, as in how to document, what is needed etc... Rey81 (talk) 19:06, 6 September 2008 (UTC)[reply]

Merging

I think it is pretty obvious it should be merged with Data_Flow_Diagram. Lewispb 10:33, 4 April 2006 (UTC)[reply]

I'll tag it. Melchoir 23:29, 13 April 2006 (UTC)[reply]

Agreed. There's a lot I could write on this too... — Phil Welch (t) (c) 23:45, 1 May 2006 (UTC)[reply]

Who's going to do the merging? If I can find some free time I'll have a go. TerrorBite 04:50, 4 May 2006 (UTC)[reply]

Done. Albanaco 18:48, 9 May 2006 (UTC)[reply]

An article about a diagram without a diagram!

Can someone who knows the correct symbols etc. make a complete data flow diagram, including as many of the standard symbols as possible, and add it to the top, or near top of the article - it seems stupid to try to describe a diagram without an actual example to look at!--Wierdy1024 22:19, 4 June 2006 (UTC)[reply]

I was planning to do that, but I'm a bit swamped with life right now. If no one beats me to it, I'll write up a DFD about Wikipedia, and post it to Wikipedia. — Philwelch t 02:05, 5 June 2006 (UTC)[reply]

That would be awesome Philwelch, if you could squeeze out the time...Regards to all--The world salutes the Rising Star...Try to be One 14:01, 8 December 2006 (UTC)[reply]

A DFD of Wikipedia? Hoo-boy, "That way lies insanity!" ;-) But as a non-expert, knowledge-seeking passerby, I too notice the irony of an article about a diagram without a diagram. Ditto for the Activity diagram stub that user 202.92.102.220 mentions below. Fortunately, the references have some diagrams.

Kkken 11:37, 14 January 2007 (UTC)[reply]

Criticism of DFDs

Perhaps we should include a section on the problems/limitations of using DFDs for system analysis and design. A reference to use cases, activity diagrams as a better solution?

Good idea, if it could be kept brief, encyclopedic, and NPOV. Like the pros/cons sections in the use cases article. Bad idea if it just turns such a section (and this Talk page) into a Hyde Park of rhetoric and debate. I've actually seen people get hot under the collar on subjects like DFDs.

Can you come back to write the problems/limitations section? I see from your contributions page and your Talk page that your IP Address has so many users, it's been blocked unless they each sign in as a member.

Kkken 11:37, 14 January 2007 (UTC)[reply]

The DFD shown here isn't even close to how a DFD works. You're missing the primary purpose of the DFD, and that is to debug requirements. I will check back and see if I can't help. jim4004 —Preceding unsigned comment added by Jim4004 (talk • contribs) 17:01, 9 December 2008 (UTC)[reply]

Data flow diagram

Real time examples for the data flow diagram for "Top-down approach" and "Event partitioning

approach" will leads to understand the concept well. data flow diagram is useful when we make project —Preceding unsigned comment added by 116.74.114.139 (talk) 04:37, 14 October 2008 (UTC)[reply]

Guido De Marco?

What does Guido De Marco, former President of Malta, have to do with structured programming techniques? Could this be a miss-attribution. There is a Thomas (Tom) De Marco, who is well known in data processing and wrote a book "Strurtured Analysis and System Specification", 1978, Yourdon Press. I think that's the De Marco related to this article.

I took a course at UC Berkeley circa 1982 that used his book as a text and it changed my whole outlook on systems development. Tom De Marco deserves a great deal of credit for 'raising the consciousness' of a whole generation of programmer/analysts.

So unless someone can document Guido's contributions to Computer Science, I would like to see this corrected...

Respectfully Yours,

FrejaDog (talk) 21:10, 10 March 2008 (UTC)[reply]

I am sure you are right! I have removed some pretty obvious vandalism from the article on Guido de Marco (unless it was an honest misidentification), and also the photo of him in Data_flow_diagram. I am not sure how the Data_flow_diagram article should be updated to give credit to Tom de Marco - I am pretty sure he is not a coauthor of the book, and it looks like there might have been a photo of Tom de Marco at some point, but it was deleted because of fair use problems. Can you fix? Thanks. Jpaulm (talk) 00:07, 11 March 2008 (UTC)[reply]

Thanks for responding. I'm sure Guido is also pleased, as is my wife who is part Maltese.

Tom De Marco is the sole author of the the book I'm referring to. The ISBN is 0-13-854380-1. Some how Yourdon Inc has the copywrite but they didn't author the book. I presume that their involvement was financial.

"Structured Analysis and System Specification" by De Marco was published by Prentice Hall as part of their software series. I think that it was one of the earliest books to describe structured analysis using data flow diagrams. An interesting aspect of De Marco's approach is his emphasis on a recursive and iterative style; diagrams are to be drawn only in pencil, shared and discussed, to be used as vehicles of communication and to resist the temptation to treat them as static icons, and, most importantly, a willingness to 'rip it up' and start over again. Later approaches, such as Yourdon's work, become, in my opinion, entirely too formal and technical, with too much emphasis on the methodology itself.

Most systems people are only familiar with the Yourdon work, and therefore rightly complain that Structured Analysis and Data Flow is too formal and cumbersome to be effectively used in the 'real' world.

Regards, FrejaDog (talk) 16:47, 11 March 2008 (UTC)[reply]

Inconsistent Elements

I am working on developing some documentation for a system and hit this topic for pointers. One thing I noted is that the elements are defined with certain shapes at the start of the topic, but the shapes used in the actual diagram examples are inconsistent.

The text indicates that processes (functions) are depicted with circles and entities are depicted with rectangles - I believe this is accurate. The example diagrams have these reversed. —Preceding unsigned comment added by Rsbradley (talk • contribs) 17:04, 8 August 2008 (UTC)[reply]

Gane and Sarson

Should more information be given to the Gane and Sarson notation as well? 143.89.188.6 (talk) 13:00, 13 October 2008 (UTC)[reply]

Data store redirection

I'm not convinced by the redirect of data store to this page (which then doesn't really define data store, even within the context of DFDs). Surely data store would be better served by a specific definition on its own page or else a redirect to database? Furrypop (talk) 14:39, 24 November 2008 (UTC)[reply]

New example diagram(s)

I agree we need an example, but the current image diagram isn't appropriate, (the lack of arrowheads is a dead givaway.) Looking into the comments added above, I see what looks like wikipedia original artwork linked to an article named Event partitioning that looks like a good start. It's really a context diagram, and to really illustrate the point of a DFD well, we would should a level or two below that.

Burt Harris (talk) 04:44, 31 December 2008 (UTC)[reply]

Wrong example- Mixing IFD examples in DFD article

The example in the first figure in the introduction is IFD (Information Flow Diagrams) and not DFD. It do not comply with the DFD definitions. It should be added to the IFD article, and be removed from here. The examples within the text are correct. The example by Burt Harris is a Level 0 DFD but is too complex to be a starting point. Ariek (talk) 09:27, 6 March 2009 (UTC) —Preceding unsigned comment added by Ariek (talk • contribs) [reply]

"dataflow", "data flow" or "data-flow"?

Should it be "dataflow", "data flow" or "data-flow"? This article currently uses all three forms.

"Modern Structured Analysis" by Edward Yourdon (Prentice-Hall, 1989, ISBN 0-13-598632-X), and the Structured Analysis Wiki uses "dataflow", the first listed form.

--Mortense (talk) 14:08, 26 July 2010 (UTC)[reply]

The correct one should be "data flow diagram" based on McGraw Hill Textbook. FYI, data flow diagram is not like writing "use-case diagram" (using dash). Ivan Akira (talk) 11:24, 28 September 2010 (UTC)[reply]