DFD for gas agency management system is used as an overview of the gas agency management without going into much detail. It normally contains the overall data flow and process of the gas agency.
This diagram helps in understanding the overall working of a gas agency like how the data flow between process and entities. In this article we will discuss level 0, 1 and 2 of the online gas agency management system.
Context level (0) DFD for Gas Agency Management System
Context level (0) DFD for Gas Agency Management System is the basic overview of the whole gas booking system. Zero (0) level DFD of online gas agency management system illustrates how information flows between the system and its external entities.
Also check: ER Diagram for Gas Agency Management System
It uses entities, processes and data flow to define the whole system. Rectangle box represents external entities, circle represents process and arrows in the diagram show the direction of data flow
There are two main external entities in this system:
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Level 1 DFD of Gas Agency Management System
Level 1 DFD of gas agency management system shows how the system is divided into subsystems (process). Each subsystem details one or more data flows and handles a different task. These all subsystems (processes) collectively make the whole system.
Level 1 DFD of gas agency management system has following sub systems or process:
New Connection application: Whenever a customer applies for a new gas connection, this process comes into picture. New connection application process records and manages all new connection application data. This information is sent to the connection & transfer request process where admin either approve or reject application.
New connection & transfer approval: This process accepts application for new gas connection and approve or reject according to the criteria. It also manage connection transfer request.
Gas connection transfer: As the name indicates, this process records all the gas connection transfer requests and sends them to the connection & transfer request process.
Gas booking: Gas booking records all the gas cylinder booking requests of existing customers.
Gas delivery: Gas delivery receives all gas cylinder booking records from the gas booking process and delivers them to the customers.
Level 2 DFD of Gas Agency Management System
Level 2 DFD of gas agency management system gives a much deeper insight view of level 1 DFD. Level 2 describes each sub process and database.
Low level functionality of gas agency management system
- Customer can apply for new gas connection
- Customer can apply for gas connection transfer from one location to another location
- Existing customers can do gas cylinder refill booking
- System deliver gas cylinder to the customer
- Admin can view new connection application detail
- Admin can approve or reject connection application
- Admin can confirm cylinder refill booking status
The database of gas agency management system is composed of following:
- New connection database
- Gas connection database
- Connection transfer database
- Gas booking log database
- Gas refill delivery
The above listed data stores are responsible for storing & securing the entire gas agency management system from unauthorized access.
Now let’s discuss about some advantages of data flow diagram
- It is simple and easy to understand by user and programmer
- It represents a graphical view of the entire system
- All system components are detailed and explained in the system
- It describes all sub process and data store
So we have discussed three levels 0, 1 and 2 of gas agency management system. Each level diagram has its own importance in data modeling.