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  1. #1
    Join Date
    Sep 2003
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    3

    help on database modelling

    Hi,

    I'm fairly new to database modelling.
    I need some pointers on how to model a good database, like what attribute an entity should has, how to parse your data, etc.

    FYI,
    I'm developing a large database for a medical application to locate medical entities (hospitals, doctors, etc.) and retrieve their infos.
    there will also be a realtion between doctors and hospitals concerning the practice schedule and location of practice.

    any help would be greatly appreciated, even general rule of thumbs (I really am a newbie at this).

  2. #2
    Join Date
    Sep 2002
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    UK
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    Re: help on database modelling

    This is not something you can learn by getting a few tips on this forum. Go to a book store (e.g. Amazon) and search for "database design", and find a recommended book suitable for a beginner.

    I can't understand why organisations entrust the development of (presumably important) "large databases" to people who have zero experience. No disrespect to you (we all have to start somewhere), but they presumably wouldn't ask you to design a new hospital wing without knowing you to be a qualified architect first, would they?

  3. #3
    Join Date
    Sep 2003
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    3

    Re: help on database modelling

    Originally posted by andrewst
    This is not something you can learn by getting a few tips on this forum. Go to a book store (e.g. Amazon) and search for "database design", and find a recommended book suitable for a beginner.

    I can't understand why organisations entrust the development of (presumably important) "large databases" to people who have zero experience. No disrespect to you (we all have to start somewhere), but they presumably wouldn't ask you to design a new hospital wing without knowing you to be a qualified architect first, would they?
    well I'd been exposed to larger DB than this (in the entity relationship sense). I just never design a DB model from bottom up before. not to disrespect any professional DB people out there, but I always thought modelling DB doesn't involve any complicated science. I'm just an apprentince BTW, someone else is doing the design actually, I'm just helping.

    well, according to my inexperienced gut feeling, this DB should be enough with a few tables with lots of tuples in them.
    my initial design I partition a hospital entity into: general info, location, contact, a table for fixed values and a table for varying values.
    anyone see anything wrong with this?

    if this subject is too vast to be discussed here please tell me, otherwise don't worry to use any DB jargons, I already have a reference book.

  4. #4
    Join Date
    Sep 2002
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    UK
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    Re: help on database modelling

    Originally posted by rxw1510
    well I'd been exposed to larger DB than this (in the entity relationship sense). I just never design a DB model from bottom up before. not to disrespect any professional DB people out there, but I always thought modelling DB doesn't involve any complicated science.
    True, it is largely a matter of common sense backed up by experience. The science (e.g. normalisation rules) defines a good database model mathematically, but it is mostly "obvious" - e.g. don't store the customer's name, address and telephone number on every order line.

    Originally posted by rxw1510
    well, according to my inexperienced gut feeling, this DB should be enough with a few tables with lots of tuples in them.
    Hmm...?

    Originally posted by rxw1510
    my initial design I partition a hospital entity into: general info, location, contact, a table for fixed values and a table for varying values.
    anyone see anything wrong with this?

    if this subject is too vast to be discussed here please tell me, otherwise don't worry to use any DB jargons, I already have a reference book.
    It really isn't possible to quality check your design based solely on the table names - though "a table for fixed values and a table for varying values" sounds odd. Try following the normalisation rules for 1st, 2nd and 3rd normal form to see if your design is properly normalised.

  5. #5
    Join Date
    Sep 2003
    Posts
    3

    Re: help on database modelling

    Originally posted by andrewst


    It really isn't possible to quality check your design based solely on the table names - though "a table for fixed values and a table for varying values" sounds odd. Try following the normalisation rules for 1st, 2nd and 3rd normal form to see if your design is properly normalised.
    normalisation? I'll check on that, thanks.

    is eliminating any redudancy thus making a DB as small as possible always the way to go when designing a DB? or is there a trap in this practice?
    could you give some more rule of thumbs for designing a DB?

  6. #6
    Join Date
    Sep 2002
    Location
    UK
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    Re: help on database modelling

    Originally posted by rxw1510
    normalisation? I'll check on that, thanks.

    is eliminating any redudancy thus making a DB as small as possible always the way to go when designing a DB? or is there a trap in this practice?
    could you give some more rule of thumbs for designing a DB?
    Take a look at this link, you may find it helpful:

    http://www.utexas.edu/its/windows/da.../datamodeling/

  7. #7
    Join Date
    Jun 2003
    Posts
    5

    Re: help on database modelling

    Originally posted by rxw1510
    I'm developing a large database for a medical application to locate medical entities (hospitals, doctors, etc.) and retrieve their infos.
    there will also be a realtion between doctors and hospitals concerning the practice schedule and location of practice.
    Here is something you can try:

    First write the use cases like:

    admin -> (locate medical entity) << include >> (locate hospital), (locate doctor)
    admin -> (retrieve info) << include >> (retrieve hospital info), (retrieve doctor info)

    assistant -> (schedule doctor) << include >> (assign doctor to location)

    etc. and then derive a DB using an approach like:
    http://www.mycgiserver.com/~nsenthil...ndbdesign.html

    Hope that helps,
    Nalla

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