5.2 - Data flow diagrams Flashcards
What is this symbol called and what does it mean?
Process
What is using the data or what it is doing to the data. This could a computer system or a set of steps a human goes through.
e.g calculate pay, reviewing an application
What is this another symbol for
Process
What is this symbol called and what does it mean?
External Entity
What or who is providing/receiving the data (most often it is humans)
This could be -
employee, customer…etc
What is this another symbol for
External Entity
What is this symbol called and what does it mean?
Data Store
Where the data is being held such as a staff database or a customer database
What is this another symbol for
Data Store
What is this symbol called and what does it mean?
Data flow
What is a LEVEL 1 DFD
Go into more detail than level 0. Processes are shown separately for a more detailed realistic review.
What is a LEVEL 0 DFD
They give an overview of how a system works, they show it in a simple manner. Processes are generalised and are not shown separately for a more basic review.
What are the connectivity rules when drawing LVL 1 DFD
- Each external entity should have at least one input or output.
- Each process has at least one input or output.
- Data flows in only one direction (This is the case for LVL 1 DFD only, but for LVL 0 you don’t have to do this, this is it makes it clear which direction the data is going.)
- Every DATA FLOW should CONNECT to at least ONE PROCESS.
What are some of the impacts that can affect the flow of information?
- Information characteristics:
information could be entered incorrectly, which could then cause a DELAY in the data flow. - Human Error:
Information could be lost due to staff not following the protocols. - Communication Breakdown:
Meetings postponed or emails unread. - Hardware failure:
This could be due to network connection or system failure.
What are the external entities in PHPS?
Customers: Initiate parcel shipments by providing details and tracking requests.
Couriers: Collect and deliver parcels, updating the system on parcel status.
Third-Party Logistics Providers: Handle parcels in regions outside the primary service area.
What are the processes in PHPS?
Parcel Registration: Captures parcel details, sender and recipient information, and assigns tracking numbers.
Sorting and Routing: Determines the optimal path for parcel delivery based on destination.
Delivery Confirmation: Updates the system upon successful delivery and notifies the customer.
What could be the data stores in PHPS
Parcel Database: Stores information about each parcel, including status and history.
Customer Database: Contains customer profiles, contact details, and preferences.
Courier Logs: Records data on courier activities, routes, and schedules.
What could be the data flow in PHPS?
Information transfer between customers and the system during parcel booking.
Real-time updates from couriers regarding parcel status.
Notifications sent to customers about parcel movements and delivery confirmations.
