Results 1 to 8 of 8
  1. #1
    Join Date
    Mar 2007
    Location
    Cork, Ireland
    Posts
    4

    Question Database design document

    Hey,

    I'm trying to document how I designed my database but I'm not really great at databases and so kind of just put tables together as I thought they best fitted. I believe the final outcome is good, I asked database lecturers to look at it and they found no major problems.
    I need to explain though for a project how I designed the db. I'm wondering is there a name given to this sort of method?
    I was planning on just explaining normalisation along with the first 3nf's and then just say I took a non standard approach, or something along those lines.

    Any advise would be grateful?

  2. #2
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    Are you talking about an ERD (Entity Relationship Diagram)?
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

  3. #3
    Join Date
    Mar 2007
    Location
    Cork, Ireland
    Posts
    4
    I'm not sure, don't think so.

    In college we're thought to normalise the database to come up with the tables using 1st normal form, 2nd normal form, 3rd normal form, etc. although usually we never went past 3NF. But I didn't take that route, or maybe I did but didn't document it
    Anyway the way I came up with my database was a non-standard approach I was told, I just looked at the fields I needed and came up with the tables.
    I need to document how I designed my database but I'm not really sure how to say it.
    I'm wondering is there a name to the method of just looking at fields and putting them into their correct table without following a formal approach.

  4. #4
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    Why in the world would you need to document HOW you came up with a database? What's important is documenting the database itself.
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

  5. #5
    Join Date
    Mar 2007
    Location
    Cork, Ireland
    Posts
    4
    College project, gotta come up with a database design doc.

  6. #6
    Join Date
    Sep 2002
    Location
    UK
    Posts
    5,171
    What you have done is what we all do once we graduate from college: use our common sense and experience to produce a fully normalised database design without going through a formal normalisation process. Well done

    What you may need to do now, for the purposes of your project, is pretend you didn't do that and:
    1) Take all the different attributes from all your tables and put them in a big list (i.e. unnormalised form) - document that.
    2) Perform the 1NF process if required (it won't be probably) and document the resulting tables
    3) Perform the 2NF process and document the resulting tables
    4) Perform the 3NF process and document the resulting tables

    The result at step 4 should of course be the set of tables you had to begin with!

  7. #7
    Join Date
    Nov 2004
    Location
    out on a limb
    Posts
    13,692
    ...erm, mebbe you should write down what you actually did...
    why you did it..
    explain your reasoning....
    explain your thought process.....
    detail why you made certain key steps....
    explain why you then applied those steps to to other elements.....
    then perhaps reconcile the eventual model with the real world by explaining why some table(s) seem unneeded but modelled that way to reflect the db not the real world criteria.

    after all the point of the coursework is to demonstrate that you understand the principles of what good db design is, and like all things in real life there is an academic viewpoint and a real world viewpoint, often they are the same or similar. But as ever there are always good reasons to break rules.

    unless of course you were supposed to go through the purely academic process of getting to 3rd NF.

    I doubt there is any practioner in the db world who actually goes through 1nf to 3nf, occasionally there are screw ups (or at least there are in my models) where something is misplaced (either as a result of a brain storm, poor design capture or the customer being cute and forgetting to mentioning something fairly critical during requirements definition)
    I'd rather be riding on the Tiger 800 or the Norton

  8. #8
    Join Date
    Jun 2003
    Location
    Ohio
    Posts
    12,592
    I think you submit your assignment as an interpretive dance.
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •