Authentication, "manage" use case and SSD diagram

Question

I am about writing a report and I have some questions to ask.

1. I am pretty sure that the authentication isn't a use case but I can use it as an included use case in the diagram. My question is: Is it correct to describe this "use case" and make his system sequence diagram (SSD)?

2. When I have a use case "manage profile", for example, do I have to describe all the sub use cases? (add, modify, delete, view) or just one of them?

3. In the DSS, is it correct to write all the scenarios in the diagram? (optional and alternative ones) or do I have to write just the nominal scenario?

Sorry for my very bad english! Thank you.

Answer 1

1.Yes you are right, you need to specify cases which are dependents on authentication using <<include>>, but some cases are not just belong to authentication, for example user has logged in, but he has no access to a certain case(keep an eye on authorization too).
  1.1: Usually engineers do not provide SD(sequence diagram) for common businesses, unless the technical(not the business) process is really complex. usually the steps are provided by SDS document to developers.

2.There is no need to look very detail at use-case diagrams, no need for view/delete/update/etc...

3.No there is no need to look in-deep in SD, unless(as I said) the process is kinda very complex, or an alternative path is really important here, but usually SD are used for describing a process of a functionality where all(imagine/expected) data are correct and there is no error and exception.

Answer 2

Thank you. I have removed the description of the UC authentication, and all "useless" details in SSD like "search a word, success/failure procedure...". I'd like to know if it is correct to say: This use case manage x is composed by 4 sub use cases: view x, add x, modify x, delete x, I make the diagram actor/4 sub UC and every time I describe the sub use case and its SSD because every sub UC needs its scenario. Or, useless?