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ERD diagram - needs checking

Hi. I want to design a simple ERD diagram.

I want a patient to be able to have an appointment. A doctor to 'hold' an appointment. An appointment to prescribe one or more prescriptions. A prescription to consist ot one or more medications. An appointment updates a patients record.

Attached is my take on this. Please could you review this and let me know if it seems integral. Thanks

Also I would like to include a many to many relationship somewhere in here  User generated image
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Joe Woodhouse

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Hi. Thanks for the reply. You raised some interesting questions. I came up with the narrative myself, I'm rehearsing for exams :)

Things I'll need more practise
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Joe Woodhouse

As a general comment I find it more useful to think it through in words and think about what's actually being modelled. At every relationship in your diagram I asked myself "is there a time where this might not be mandatory even though it is currently marked as mandatory?" (Someone doesn't pay their their invoice in full and another invoice needs to be issued for the outstanding amount.) "This is currently marked one to one - is there ever a time when there'd be more than one? (A couple or family jointly attending an appointment with each of them being treated.)

Once you go through it in words like that, the diagram itself is easy. Do the diagram after the analysis, not as *part* of the analysis. :)