Sequence Diagram and its Notations - Part I
Let’s get started.
A sequence diagram is a type of interaction diagram which describes how and in what
order a group of objects work together.
Also known as an event diagram or an event scenario, these diagrams are an excellent
way to visualise and validate various runtime scenarios. These scenarios, in turn, help
predict how a system will behave and discover the responsibilities a class needs in
modelling a new system.
Similarly, sequence diagrams are used mainly by business professionals and software
developers to understand requirements for a new system or to document an existing
process.
,Moreover, these diagrams are primarily used to show the interaction between objects in
sequential order.
For a better understanding, let’s take a look at an example.
Let’s suppose you’re calling one of your friends, say, Jenny. In that case, how would the
conversation usually proceed?
Well, first, you’d make a call. Then as soon as she takes the call, she’d greet you with a
‘hello’, and you’d greet her back. Next, each of you might take turns asking each other
how it’s going. Then, you’d most probably discuss the reason why you called her. So, the
communication between you and your friend would usually proceed one after another in
this manner.
Just like that conversation between you and your friend, sequence diagrams represent
the flow of messages between different elements within a system.
, Much like the use case diagrams, these diagrams can also be used by non-technical
personnel to explain the system’s flow and how different objects interact with each other
within it.
However, sequence diagrams are especially used by technical specialists to document
how an upcoming system should function.
Additionally, system architects and developers can use this diagram to forge out the
system’s object interactions, thus helping to enhance the overall system design.
Let’s get started.
A sequence diagram is a type of interaction diagram which describes how and in what
order a group of objects work together.
Also known as an event diagram or an event scenario, these diagrams are an excellent
way to visualise and validate various runtime scenarios. These scenarios, in turn, help
predict how a system will behave and discover the responsibilities a class needs in
modelling a new system.
Similarly, sequence diagrams are used mainly by business professionals and software
developers to understand requirements for a new system or to document an existing
process.
,Moreover, these diagrams are primarily used to show the interaction between objects in
sequential order.
For a better understanding, let’s take a look at an example.
Let’s suppose you’re calling one of your friends, say, Jenny. In that case, how would the
conversation usually proceed?
Well, first, you’d make a call. Then as soon as she takes the call, she’d greet you with a
‘hello’, and you’d greet her back. Next, each of you might take turns asking each other
how it’s going. Then, you’d most probably discuss the reason why you called her. So, the
communication between you and your friend would usually proceed one after another in
this manner.
Just like that conversation between you and your friend, sequence diagrams represent
the flow of messages between different elements within a system.
, Much like the use case diagrams, these diagrams can also be used by non-technical
personnel to explain the system’s flow and how different objects interact with each other
within it.
However, sequence diagrams are especially used by technical specialists to document
how an upcoming system should function.
Additionally, system architects and developers can use this diagram to forge out the
system’s object interactions, thus helping to enhance the overall system design.
