Question

Compair usecase diagram with context diagram modeling in depth. for softwear requirement

Answer 1

Context diagram

context diagram is used to show the flow of data in a system.
context diagram does not give the detailed description.
further levels of dfd can give details.
context diagram focuses on flow of information/data.
in context diagram, user(Entity) is represented by a rectangular box.
context diagram gives the context of entire system
DFD shows that how information is being transformed in a system.

use case diagram

use case diagram is used to show one feature of an entire(big) system
system.
use case focuses on the sequence of events.
use case shows that how the system will be used by the actor to accomplish the task.
in use case, user(Actor) is represented by human symbol.