UML Diagram - Sequence Diagram

A UML sequence diagram provides insight and overview of object interactions arranged in a time sequence. It shows the objects and classes that are involved in a scenario and a sequence of messages exchanged between objects needed to carry out functionality.

Model your Diagrams on the Dragon1 Platform

Dragon1 is fit for purpose for UML modeling. Create you trial account now and start creating UML Models right away.

www.dragon1.com/create-trial-account

When to Draw an UML Sequence Diagram?

A UML sequence diagram shows the scenario (flow of events) in one single use case.

The flow of messages in the sequence diagram is based on the story told by a use case.

If you want to draw a sequence diagram, you normally need to draw a use case diagram and write down a description of what the use case in question actually does.

The Elements of a Sequence Diagram

A sequence diagram consists of elements:

• Lifeline Notations
• Activation Bars
• Message Arrows

Below you see three examples of these elements:

UML Lifeline notation with an Actor symbol

UML Activation bar

UML Message Arrows