5.2
- Created by: Lmula
- Created on: 15-05-18 12:31
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- Data Flow Diagrams(DFDs)
- External entities
- external entities are sources of the data that is input into the system and those to whom data that is output is sent and who are external to the system itself.
- processes
- these are ways in which the data in the system is collated. In the example, there would be one central process which would collate the scores and comments made by individual tutors into one overall report for each student.
- Data stores
- Data stores represent any real world store of data held in the system. This could be a computerised database, but could also be an inbox on someones desk.
- data flows
- these are the flows of data between the entities and the processes.
- the rules for drawing level 1 DFDs
- At least one input or output for each external entity
- Data flows only in one direction
- Every data flow is labelled
- every data flow connects to at least one process
- At least one input data flow and?
- External entities
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