5.2 - Data Flow Diagrams

Front

What is a data flow diagram (DFD)?

Back

A visual representation of how data is transferred within a system or organisation.

Front

What are the common symbols used in a DFD?

Back

External Entity, Process, Data Store, Data Flow.

Front

What is an example of an external entity in a DFD?

Back

Examples include Employee or Customer.

Front

What is an example of a process in a DFD?

Back

Examples include Calculate Pay or Review Application.

Front

What is an example of a data store in a DFD?

Back

Examples include Staff Database or Customer Database.

Front

What is the difference between Level 0 and Level 1 DFDs?

Back

Level 0 DFDs show data transfer in a simple manner, while Level 1 DFDs show data transfer in a more detailed manner with individual processes expanded.

Front

What are the rules for drawing a Level 1 DFD?

Back

Data flows only in one direction, every data flow is labelled, every data flow connects to at least one process, and there is at least one input or output for each external entity.

Front

What are some impacts affecting the flow of information?

Back

Information characteristics, human error, hardware failure, and communication breakdown.

Front

Give an example of how information characteristics can affect data flow.

Back

Information entered incorrectly can cause delays.

Front

Give an example of how human error can affect data flow.

Back

Information can be lost or staff may not follow protocol.