Normalization

  • Comments posted to this topic are about the item Normalization

  • Aaah, back to basics 🙂

    Thanks for the question!

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  • Good Question

    Srikant

  • going back to basics...ohh good remember the concepts from basic level...

  • Great question. 😛

  • Basic but a great question. Some more like this would be fantastic.

  • Nice question and an interesting example. Would renaming the columns "Telephone 1" and "Telephone 2" to "Home Phone" and "Mobile Phone" mean that the table was then in 1NF?

  • Nice question and an interesting example. Would renaming the columns "Telephone 1" and "Telephone 2" to "Home Phone" and "Mobile Phone" mean that the table was then in 1NF?

    I would say no, because there can be other categories of phone, such as Business Phone. The phone number may not be the best example because it could be said that "I only want two phone numbers", in which case an argument can be made for having the columns in the main table. Not a great argument, as the single column in a seperate table still makes queries and searches easier, and if someone would ever come a long and decide they want to track three phone numbers, the seperate table is much easier to implement, as it is already so.

  • Richard Warr (4/27/2011)


    Nice question and an interesting example. Would renaming the columns "Telephone 1" and "Telephone 2" to "Home Phone" and "Mobile Phone" mean that the table was then in 1NF?

    Great thought. It's funny how even a definition of something so basic, like 1NF, can still be fuzzy. If you're going by Chris Date's definition, his fourth rule states "Every row-and-column intersection contains exactly one value from the applicable domain (and nothing else)." Now, are all categories of telephone numbers (mobile, home, work etc.) considered of the same "domain"? Not to mention, adding a second telephone number field would mean one of them could possibly be null. Null fields, to some, is also a violation of 1NF.

    ... I think it's a trick question and I want extra points!

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  • Excellent question.

    Jason...AKA CirqueDeSQLeil
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  • Basic but very needed fundamental question

  • Richard Warr (4/27/2011)


    Nice question and an interesting example. Would renaming the columns "Telephone 1" and "Telephone 2" to "Home Phone" and "Mobile Phone" mean that the table was then in 1NF?

    I am not the db design guru, but from my understanding, that would be incorrect. The "use" of that property is different, but both home and mobile are the same type of property in relation to the entity.

  • Good question.

  • Nice question Steve.

    We never have to guess or debate an answer with you.

  • SanDroid (4/27/2011)


    Nice question Steve.

    We never have to guess or debate an answer with you.

    Ha! I've made plenty of mistakes and had some sketchy questions. 😛

    I am trying to get better and have learned to write questions that probe a bit without trying to trick someone.

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