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  1. #1
    Join Date
    Mar 2011
    Posts
    1

    Unanswered: efficiency question

    Hi guys,

    i'm designing a database and i came to this question.

    now i have a number of cars from different brands. all car brands have some
    common properties (column) , but there are properties belong to specific
    brands.

    so which is better: to create a table for each brand having common
    properties and special properties ;or to create a table for common properties
    which will have differnt brands and a table for each brand having only its
    special properties ?

    i appreciate your help.

  2. #2
    Join Date
    Jan 2003
    Location
    Nottinghamshire, UK
    Posts
    364
    Hi htb & Welcome

    It's a bit of a Judgement call based on how many brands of Cars you expect & how specific the differences will be.

    As a General Car Trader you may have 500 Brands in a year and not require specific details so much, As a Peugot Dealer you may have 20 Brands and want to record high amounts of detail.

    Just ask yourself can you imagine creating a database with 500 tables to begin with ?

    Something to look at would be using Supertypes and Subtypes Lesson 5: Supertypes and Subtypes be carefull though it does have disadvantages later on for beginners.

    Good Luck

    GW
    "Everything should be made as simple as possible, but not simpler." - Albert Einstein
    "Everything should be made as complex as possible, so I look Cleverer." - Application Developer

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