Question

How do know when to model an activity diagram and when to model a sequence diagram?

Answer 1

-Similarities between Sequence and Activity diagrams:

- UML diagrams are both sequence diagrams and activity diagrams.

- The control flow of messages is represented using both sequence and activity diagrams.

Sequence Diagram

- The diagram of the sequence represents the UML used to visualize the call sequence in a system that is used to perform a particular functionality.

- The Diagram Sequence shows the flow of messages from one object to another object.

- For the purpose of dynamic modeling, sequence diagrams are used.

- The sequence diagram is mainly used to represent a system's time order.

Activity Diagram

- The Activity diagram represents the UML that is used to model a system's workflow.

- The activity diagram shows the flow of the message from one activity to another.

- The activity diagram is used for functional modeling purposes.

- To represent the execution of the process, the Activity Diagram is used.

-Sequence Diagram:- It describes an interaction in a chronological order among a set of objects participating in a collaboration; it shows the objects engaging in the interaction by their "lifelines" and the messages they send to each other.

UML Sequence diagrams are diagrams of interaction that detail how operations are performed. In the context of a collaboration, as sequence diagrams can be used to capture the interaction between objects, one of the primary

uses of sequence diagrams is in the transition from requirements expressed as use cases to the next and more formal refining stage. Use cases are also refined into one or more diagrams of sequences.

When to model Sequence diagram:

If we want to look at the behaviour of several objects within a single use case, we should model sequence

diagrams. Sequence diagrams are good at explaining collaborations among objects; they are not so good at

describing the behaviour precisely.

1. In various situations, model and document how the system will behave.

2. Validate the logic of operations and functions which are complex.

-Activity Diagram:- The activity diagram is described as a UML diagram that focuses instead of execution on the

execution and flow of a system 's behaviour. It is also called a flowchart of object-orientation. Activity diagrams

consist of activities made up of actions that apply to the technology of behavioural modelling.

When to model Activity diagram:

To model business processes and workflows, activity diagrams are used. In software modelling as well as business

modelling, these diagrams are used.

Activity diagrams are most commonly used for,

1. Model the workflow, which is easily understandable, in a graphical way.

2. Model the execution flow of a method between different entities.

3. Model the specific information used inside the system about any function or algorithm.

4. Business process models and their workflows.

5. Capture a system's dynamic behaviour.

6. Generate high-level flowcharts to represent any application's workflow.

7. Model a high-level view of a distributed or object-oriented system.