context diagram(1)
TRANSCRIPT
![Page 1: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/1.jpg)
Context Diagram – Data Flow Diagram
![Page 2: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/2.jpg)
What is DFD ?
Data Flow Diagramming is a means of representing a system at any level of detail with a graphic network of symbols showing data flows, data stores, data processes, and data sources/destinations.
Usually this technique starts with a very high level graphical representation showing and overall picture of the business and processes and continues down to the lower levels of the process through the presentation.
![Page 3: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/3.jpg)
The purpose of data flow diagrams is to provide a semantic bridge between users and systems developers.
The diagrams are:
graphical, eliminating thousands of words logical representations, modeling WHAT a system does, rather than physical models showing HOW it does it hierarchical, showing systems at any level of detailJargonless ,allowing user understanding and reviewing.
![Page 4: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/4.jpg)
Context Diagram
• defines the scope of the system by identifying the system boundary
• contains: – one process (which represents the
entire system)– all sources/sinks (external entities)– data flows linking the process to
the sources and sinks (external entities)
![Page 5: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/5.jpg)
![Page 6: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/6.jpg)
![Page 7: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/7.jpg)
Some Examples ER / CONTEXT DIAGRAM / DFD
![Page 8: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/8.jpg)
If Journals are included
How will the ER change ?
![Page 9: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/9.jpg)
![Page 10: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/10.jpg)
![Page 11: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/11.jpg)
BOOK ISSUE MANAGEMENT
SYSTEM
MEMBERSHIPMANAGEMENT REPORT
MANAGEMENT
Request forMembership
Issue / Denial ofMembership
CATALOGUE SYSTEM
Supplies Book Info / Issue Details
Penalty Amount
![Page 12: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/12.jpg)
What happens if there are constraints On the number of issues of booksIs 2nd level DFD needed ?
![Page 13: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/13.jpg)
![Page 14: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/14.jpg)
level 1 data flow diagram for Inventory System
![Page 15: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/15.jpg)
level 2 data flow diagram for process 4, Reorder stock Note the numbering scheme. Processes 4.1, 4.2, 4.3, 4.4, and 4.5 are sub-processes of level 1 process 4.
![Page 16: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/16.jpg)
![Page 17: Context Diagram(1)](https://reader036.vdocuments.us/reader036/viewer/2022081421/5531954f4a79595c2b8b4ade/html5/thumbnails/17.jpg)