What were the most important concepts you learnt about data and process modelling this week?
The basic symbol set used in DFD’s is the most important concept that I have learned this week. My reasoning is because if the basic sysbols are not understood, there is no possible way that a context diagram or a diagram 0 DFD can be drawn successfully.
Why do you think those concepts are important?
These concepts are a vital tool used to descibe an information system and how input data is transformed into useful information. Understanding just what a process is and the relationship between symbols is critical if the information system is to be described correctly.
What are the data and process modelling concepts that are still causing you the greatest problems?
I am still having some difficulty in coming to grips with the relationship between the context diagram and diagram 0 DFD. I understand that a diagram 0 is a more detailed view of each entity in the context diagram. However, using p 159 of the textbook as an example; why was the grading system process symbol (process 0) replaced with a datastore? Is it because the expanded view does not require the symbol because you are looking inside it? In addition while I understand the basic concept of functional primitives, how do you know when you are at the lowest level possible?
How might the problems you are having be solved?
Further research, use of the course bulletin board, asking these questions directly to a lecturer and much more practice!
August 7, 2006 at 7:22 am
G’day Andrew,
The process 0 symbol is not just replaced with the data store – though that’s what the layout of the diagram can lead you to believe.
I’m going to post a response to the course discussion forum that I hope will explain this in more detail. Check it out and let me know if there is still something that is unclear.
David.