Which of the following statements are TRUE? I. The context diagram should…
2009
Which of the following statements are TRUE?
I. The context diagram should depict the system as a single bubble.
II. External entities should be identified clearly at all levels of DFDs.
III. Control information should not be represented in a DFD.
IV. A data store can be connected either to another data store or to an external entity.
Answer: C. I and III — Evaluate each statement about Data Flow Diagrams (DFDs): I. True. In a context diagram, the entire system is represented as a single process or bubble, with…
- A.
II and III
- B.
II and III
- C.
I and III
- D.
I, II and III
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Correct answer: C
Evaluate each statement about Data Flow Diagrams (DFDs):
I. True. In a context diagram, the entire system is represented as a single process or bubble, with external entities and data flows shown around it.
II. False. External entities are identified at the context level. Lower-level DFDs decompose internal processes; external entities are not required to be shown at every level.
III. True. A DFD represents data movement and transformation, not control flow or control information.
IV. False. A data store should be connected through a process. Direct data-store-to-data-store or data-store-to-external-entity connections are not valid DFD flows.
Therefore, only statements I and III are true.