Domain Understanding and Modeling

Week 4 - Data flow diagram - Part one


  • Why do we make DFDs?
  • Business processes vs data processes
  • DFD Notation 
  • How to make DFD?


Slides:

Chyba: Odkazovaný objekt neexistuje nebo nemáte právo jej číst.
https://is.muni.cz/el/fi/podzim2023/PA116/um/en/DUM_06_DFD_ENG.pdf


Recorded lecture in Czech:

Chyba: Odkazovaný objekt neexistuje nebo nemáte právo jej číst.
https://is.muni.cz/el/fi/podzim2023/PA116/um/vi/85432032/


Seminar briefings in English:

** Seminar tasks and their order has been updated this year, so they are covered by two different briefings as recorded last year**

Chyba: Odkazovaný objekt neexistuje nebo nemáte právo jej číst.
https://is.muni.cz/el/fi/podzim2023/PA116/um/seminar_briefings/Event_partitioning_Context_Diagram_DFD.mp4
Chyba: Odkazovaný objekt neexistuje nebo nemáte právo jej číst.
https://is.muni.cz/el/fi/podzim2023/PA116/um/seminar_briefings/Mockups.mp4



Seminar tasks

1) Event partitioning    [2 pts]

  • Cycle across different actors and write down life events / requests which trigger a response from a system
  • These requests represent a more detailed analysis of use cases - particular requests (represented by data inputs)
  • When paired with a response from IS (data outputs), these pairs represent "data microtransactions" which can be aggregated into data flow diagrams = bottom-up approach (creating DFD will be a task for next seminar).
  • Events can be of 3 types:
    • data (F) - most common, data driven
    • temporal (T) - triggered by a timer, objectively or subjectively
    • control (C) - triggered by sending a signal, no additional data from user required 
  • To obtain points, write down 30-50 events and denote their type

2) Screen mockups / wireframes    [3 pts]

  • easy to work with and powerful tool to harvest domain knowledge from end users of IS with low requirements for technical knowledge
  • when presented (or drawn together with) an end user, it can help identify events, but also sequence of business steps (we did it last week) or data model - ERD (will be done later in semester)
  • To obtain points, create a sequence of 3 screen mockups which reflect specific use case / business process
  • recommended tool is https://balsamiq.com , but any other tool is accepted