Data Flow Diagram II

What can a level 1 DFD include that a context diagram cannot?

• Data Stores

• Multiple external entities

• Direct entity to entity communication

• direct data store to data store communication

 What does this notation represent in a data flow diagram?

• Decision

• Entity

• Process

• Datastore

What does this notation represent in a data flow diagram?

• Process

• Sink

• Source

• Entity

Choose the response(s) that is correct regarding the levels of data flow diagramming

• A level 1 DFD notates the main sub-process which together forms the complete system.

• A level 1 DFD does not include external entities

• A level 1 DFD MUST include one and only one external entity

• A level 1 DFD is an “exploded view” of the context diagram.

A process is:

• a single piece of data

• a collection of data

• an activity or a function that is performed for some specific business reason

• a person, organization or system outside of the system

A new patient calls up an optometrist office to make an appointment. On a DFD diagram, the new patient would be represented by which symbol?

• A data flow

• A process

• An external entity

• A data store

Ruth is an analyst. On her DFD diagram she has just placed a process. She will

• give it a noun description phrase, like 'Inventory-process-1'

• give it only a number - and depending on whether it is a major process (a whole number) or a subsidiary process (a whole number with a decimal point and value - like 1.3)

• give it a sentence name, like 'Customer arrives at checkout counter'

• give it a number and a verb phrase name, like 'search inventory'

A payroll data flow diagram has a data-store called "Accumulated Salary Database". At one stage in the DFD, a process "Calculate YTD-Taxes" gets data from that data store, updates it in the process, and writes it back to the database. The diagram should show:

• a single line with arrows on both ends labeled "YTD Payroll Details"

• two separate data flow lines but each with the same name "YTD Payroll Details"

• a line out of the data store labeled "Current YTD Payroll Details" and a line into the data store labeled "Updated YTD Payroll Details"

• a dashed line with arrows on both ends labeled "YTD Payroll Details"

On the context diagram, Tim has a process called "Start Process". It has one output data flow 'Initial Data' and no input data flows. Based on DFD rules, is this correct?

• TRUE

• FALSE

Which of the following are examples of data stores in the image provided?

• Student Answer

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• Correct Answer

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