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Carl Ret02
Carl Ret02

Reputation: 19

Making a Database as an Actor using Use Case Diagram, and the correctness of the whole diagram

I'm stuck and confuse if I need to identify Database as an Actor since the database is given in the scenario.

I tried first to make it as an actor since based on the scenario, the data needed is from database. I Also tried to create a use case for the whole scenario but not sure if correct.

Here is the link of the scenario: https://justpaste.it/7tljo

The Use Case Diagram I created: enter image description here

Upvotes: 1

Views: 3042

Answers (1)

Christophe
Christophe

Reputation: 73530

Is the database an actor?

A database should in principle not be an actor in a use-case. Two reasons for that:

  1. A database is in general a component used to implement a system, so it is part of the system's internals (even if it is bought from a third party and installed on a separate server). But actors must be external to the system.
  2. Actors may represent separate systems that interact with the system. But some degree of autonomy is expected since they play a role in the case: either the system actor supports the use-case, like a human actor could do, or it uses the system for achieving its own goals.

More generally, some useful question to ask yourself about candidate system actors: does the business need to know? are users or business stakeholders interested in? is the system actor a system that would be useful if your system wouldn’t exist? could we imagine the same use case with a human user instead of a system actor?

Is the overall diagram ok?

Syntactically, the diagram looks ok. But it methodically break down features/functionality in smaller pieces. This is called functional decomposition: Although it is not forbidden by UML, it leads to complex and unreadable diagrams. This is why the use-case community recommends not to do this, and instead prefer to align use case on user goals.

Hint: if you start to think about workflows, order of operations or user interface components when you design your use-cases (e.g. review contract, approve contract), you probably should consider using an activity diagram instead.

Upvotes: 1

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