Ye Olde Clue

Tried out on someone else

This is a reply, basepost

Nothing like trying out modelling someone else's model to test your system. OK, so I downloaded the dia file from this page on the Manchester Computer Science website to see what their models look like today. Pretty much as they used to, but it looked simpler to me than I remember. Anyhow, I did the obvious of mapping their model to a textual description:

entity Artist:
    simpleattributes artisticname genre

entity Manager:
    simpleattributes ID name1 telephone

entity ContractInfo:
    simpleattributes contractID data_from data_to duration1

entity MasterTrack:
    simpleattributes trackID working_title duration2

entity SoundEngineer:
    simpleattributes sound_eng_ID name2

entity FinishedTrack:
    simpleattributes version final_duration released_title

entity Album:
    simpleattributes album_ID title

relation ManagedBy(Artist,Manager)
relation HasContract(Artist,ContractInfo)
relation RecordedBy(MasterTrack,Artist)
relation EditedBy(SoundEngineer,MasterTrack)
relation OriginatesFrom(FinishedTrack,MasterTrack)
relation GroupedOn(FinishedTrack,Album)
#       simpleattributes sequence
relation CreatedBy(Album,Artist)

This worked pretty well, but we have some issues:

• No weak entities
• No calculated attribute
• No repeated attributes
• No attributes on relations
• No way of indicating an attribute is a key
• No way of indicating an attribute is a partial key
• You'll note we have some odd attribute names: duration1, duration2, name1, name2 - this is due to the naming of attributes being global rather than scoped.
  

(Interestingly there's no key on there which is a composite key)
So, what does the resulting diagram look like?
And if I say so myself, I think it's a lot prettier. I used to think that pretty was just a nice thing, but these days I really think it matters quite a lot more than I used to, if only for one simple reason - some one will stay and look and stare at and think about something pretty for longer than not. The other thing is the auto layout has also made it clear that the model they're using is alot simpler than it appeared at first glance.

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