"David M. Karr" wrote:
>
> In an experimental application I'm building, I have two entities, named
> "Student" and "Class" (no name conflict, I use "ClassBean", "ClassHome", etc.).
>
> I also have an entity named "StudentClassGrade". This essentially reflects a
> "valued association", referencing a Student and Class, and containing a Grade
> value.
>
> My first question is, what should be the types of the "Student" and "Class"
> references in "StudentClassGrade" be? Should they be the remote references, or
> the primary keys? The primary keys of "Student" and "Class" are, respectively,
> "String ssn" and "String name".
>
> Then, dependent on that, my PK class for "StudentClassGrade" will be a compound
> key. I'm fairly certain this should contain the two primary keys of the
> associated Student and Class, but I'm not quite sure how this should work.
Yes that would be reasonable.
Then you can add methods: findByStudent and findByClass to the home interface
of your 'relationship' entity. When you find an entity, call a method
getGrade() to fetch the grade.
> I'm having a lot of trouble finding good documentation and examples for this
> sort of thing. I've found umpteen examples of trivial beans and PKs, but
> nothing like this. I was hoping the new "Professional EJB" book would cover
> this well, but it doesn't.
>
> --
> ===================================================================
> David M. Karr ; Best Consulting
> [EMAIL PROTECTED] ; Java/Unix/XML/C++/X ; BrainBench CJ12P (#12004)
>
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--
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