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Is database an actor in sequence diagram?
In a use case model, actors are humans or external system that interact with the system for the purpose of achieving a use case (i.e. an intent of an actor or a business requirement). For this reasons, databases are usually not part of the use case diagrams.
Does sequence diagram need an actor?
1 Answer. It is absolutely OK. Actors are one of the main elements in UC diagrams, but not in sequence diagrams.
What is a boundary in a sequence diagram?
A Boundary is a stereotyped Object that models some system boundary, typically a user interface screen. A Boundary is used in the conceptual phase to capture users interacting with the system at a screen level (or some other boundary interface type). It is often used in Sequence and Robustness (Analysis) diagrams.
Can you have multiple actors in a sequence diagram?
We can have multiple actors in a sequence diagram. For example – Here the user in seat reservation system is shown as an actor where it exists outside the system and is not a part of the system. Lifelines – A lifeline is a named element which depicts an individual participant in a sequence diagram.
Is the database in a sequence diagram an entity?
Clearly, your database is not an entity according to this understanding. Even if you would develop your own database from scratch as part of the system. < > and < > are non standard stereotypes. But if you need to access the external database, you’d need a boundary object acting as connector/gateway.
What does a lifeline mean in a sequence diagram?
An Actor is a user of the system; user can mean a human user, a machine, or even another system or subsystem in the model. A Lifeline represents a distinct connectable element and is an individual participant in an interaction. Boundary elements are used in analysis to capture user interactions, screen flows and element interactions.
When to use sequence diagram or interaction diagram?
A sequence diagram is the most commonly used interaction diagram. An interaction diagram is used to show the interactive behavior of a system. Since visualizing the interactions in a system can be a cumbersome task, we use different types of interaction diagrams to capture various features and aspects of interaction in a system.