Practical-4 Design DFD (level 0 and 1) for a system

_Practical-4

Design DFD (level 0 and 1) for a system

 

l  Explain DFD symbols in brief.

ans->

-External entity:

-it is also known as sources if they are external to the system and provide data to the system.

-If they are external to the system and receive information from system then called as sinks 

-It can be people, department, other companies etc.

 

-Processes:

-it must have at least one input and at least one output.

-A process receives input and generate some output.

 

-Data Stores:

-it can be online or “hard copy “.

-It is labeled with a noun (like customer etc.).

-A data store is where a process stores data between processes for later retrieval by that same process or another one.

 

-Data flows:

-it must originate from and/or lead to a process.

It can go from process to process, but that does imply that no data is stored at that point.

-It can have one arrowhead indicating the direction in which the data flowing.

 

 

DFD Level 0 diagram of RESUME GENERATOR SYSTEM

 

 

DFD Level 1 diagram of RESUME GENERATOR SYSTEM

 

 

 

 

 

l  Write advantages and disadvantages of DFD .

ans->

-Advantages:

-it aids in describing the boundaries of system.

-It is beneficial for communicating existing system.

-A straightforward graphical technique which is easy to recognize.

-DFDs can provide a detailed representation of system components.

-It is used as a part of system document file.

 

-Disadvantages:

-It makes the programmer little confusing concerning the system.

-Physical considerations are left out.

It simply take long time to create.

 

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