1. 7M701 1 Software Engineering Data Flow Models Sommerville, Ian (2001) Software Engineering, 6 th edition: Chapter 7 http://www.software-engin.com

2. 7M701 2 Analyses and design of IS Basic techniques Process orientation (processes, activities, functions) Data orientation (data, entities, objects)

3. 7M701 3 Data-processing models Data flow diagrams are used to model the system’s data processing These show the processing steps as data flows through a system Intrinsic part of many analysis methods Simple and intuitive notation that customers can understand Show end-to-end processing of data

4. 7M701 4 Order processing DFD

5. 7M701 5 Equipment procurement process

6. 7M701 6 Data flow diagrams DFDs model the system from a functional perspective Tracking and documenting how the data associated with a process is helpful to develop an overall understanding of the system Data flow diagrams may also be used in showing the data exchange between a system and other systems in its environment

7. 7M701 7 Process models Process models show the overall process and the processes that are supported by the system Data flow models may be used to show the processes and the flow of information from one process to another

8. 7M701 8 Example process modelling: IDEF0 /activityblock control output input mechanism / means

9. 7M701 9 Make client brief Make a design client brief design offer Submit an offer Demand for a design and offer on behalf of a house project manager / client/ computer system

10. 7M701 10

11. 7M701 11 Key point Data-flow diagrams may be used to model the data processing carried out by a system. The system is modelled as a set of data transformations with functions acting on the data.