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  1. #1
    Join Date
    Nov 2005

    Can one table become 1-1 2 or 3 tables???

    I have one table : country (name , population,capital,capital_stat1 , area , second_name , bla , bla , bla ... )

    can this table become 2 tables 1-1 like :
    country ( name , population , area , second_name , .... bla bla )
    capitals ( name , capital_stat1 , other_referring_capital )

    If this is right , is possible the 2 tables become just one again or is one of these ways wrong ??? Does the effieciency counts more in the 1st or 2nd???


  2. #2
    Join Date
    Sep 2002
    Splitting one table into 2 or more tables is perfectly valid - it is called "vertical partioning". Whether it confers any benefits depends on your specific DBMS and needs. If there are 200 columns but you only want some 5 of them most of the time, then it may be more efficient to break them out into a separate table. But then again, you'll have to join those 2 tables back together for some queries, which may be less efficient. You'll have to try it out to see what works best for you.

  3. #3
    Join Date
    Aug 2004
    You will also want to consider cardinality. Can a country have more than one capital? (South Africa has 3 - Bloemfontein, Cape Town, and Pretoria)

  4. #4
    Join Date
    Nov 2005


    Yes , off course i have checked that because if i have 1 country with more than one capital then i would have a 1-N relationship.
    What if i have two 1-1 tables country(....) and capitals(...)
    and country has 50 records and capitals only 20 records??? This is the same if i had country with these 20 records having their capital and all the other would have capital = null ????
    Is it correct???

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