UML Design – Should Written Use Cases Be Consistent with Use Case Diagrams?

cruddesignumluse-case

I'm developing a video web system like YouTube where users can upload, view, update and delete their own videos (CRUD operation). Original I drawn the use case diagram like this：

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But I learned later that it's better to use one use case called "manage video" to simplify the whole diagram where there are a lager number of use cases presented, so the above diagram is modified to this one:

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However, in this way I have difficulty creating the detailed description for the "manage video" use case as the procedure of uploading video is much more complex than that of other operations and I can't summarize all of them into one single written use case. Thus I think it's better to write separate written use case for each CRUD operation. But this brings the inconsistency between the use case diagram and written use case document as the "manage video" use case in the use case diagram is not mapped to any written use case. Is it OK with that? If not, how can I solve this problem?

Best Answer

I think there is 2 factors that can make you choose between one or the other

  • Is "Manage" a classical CRUD case or is there more ?
  • Is the whole diagram already quite big ?

Now ideally depending on the result of the two questions :

  • If yes for the first -> go for "manage"
  • If no for the 1st and yes for the 2nd, go for "manage" and add another diagram showing the corresponding subcase to "manage".
  • If no for both : show all your operation in that diagram.
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