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Normalisation

  • 06-04-2011 8:39pm
    #1
    corkweb
    Registered Users Posts: 14 ✭


    Hi lads,

    I want to do 0NF to 3NF for a few databases but really can't get my head around on how to do it correctly. The examples I've found online just don't make sense to me. I've spent the last couple of hours trying to understand :confused:

    I attached an ER diagram of one of my databases. If you could show me how to solve that one, I would be able to do the rest as they're similar.

    Thanks.


Comments

  • #2
    Razzuh
    Registered Users, Registered Users 2 Posts: 184 ✭✭Razzuh


    It's not easy to normalise just from that ER diagram, I'd need a bit more description of the entities and their relatinoships, and what the attributes are representing. I think it might be pretty close to 3NF as it is though.

    Am I right in saying that dvd, personel and roles all have many-to-many relationships? i.e.
    • a dvd has 0 to many personel.
    • a dvd has 0 to many roles.
    • a role has 0 to many personel
    • a role has 0 to many dvds
    • a personel has 0 to many dvds
    • a personel has 0 to many roles

    Please reply and correct these if they're not right.

    The thing that jumped out at me is the role_id in the personel table, I'm pretty sure that's not right. What is the purpose of that?


  • #3
    Dean820
    Registered Users, Registered Users 2 Posts: 2,099 ✭✭✭Dean820


    edit.


  • #4
    corkweb
    Registered Users Posts: 14 ✭corkweb


    I think I did it in reverse.

    Here are the 0NF (I think):

    firstname
    surname
    dob
    nationality
    job_title
    job_description
    website
    twitter
    image
    dvd_title
    dvd_length
    dvd_bonuses
    release_date
    cover_art
    genre
    certificate
    studio

    Was just looking at another tutorial, can't get my head around it.
    The thing that jumped out at me is the role_id in the personel table, I'm pretty sure that's not right. What is the purpose of that?
    The roles_id is being linked to another table in VB so it displays what role he actor/director,etc play.


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