Re: Tarski school influence on Database Theory

On 2015-09-28, vldm10 <vldm10_at_yahoo.com> wrote:
> Dana ponedjeljak, 28. rujna 2015. u 09:40:04 UTC+2, korisnik Eric napisao je:
>> On 2015-09-25, vldm10 <vldm10_at_yahoo.com> wrote:
>>> On Monday, July 20, 2015 at 16:09:59 PM UTC-7, compdb <compdb_at_hotmail.com> wrote:
>>>> Besides inventing relational algebra, Codd also initiated and championed
>>>> query safety, integrity, normal forms and other issues ...

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>>> Integrity and normal forms.  Regarding the normal forms, I must say that

>>> Codd did not invent the "First normal form." ...


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>>> ... records that have a fixed length (that is, they were working with the


>>> first normal form) ...

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>>> So the idea of "First normal form" was performed and analyzed in detail


>>> before Codd. All the advantages and disadvantages of "First Normal Form"

>>> were well analyzed in very complex cases. Note that variable length of

>>> records and entities, we can not apply to relations.

>>>

>>> It is not true that Codd invented the "First normal form". Codd added

>>> "First normal form" to relational model, and he gave the name: "The

>>> first normal form"

>> 

>> Fixed length records can not possibly be the same as first normal form

>> since records are about files and first normal form is about relations.

Yes. And yes. I stand by my first two sentences. So would you please answer my question.

Maybe I could amplify the question. What definitions of "first normal form" and "fixed length records" are you using? I ask for the first because the concept seems to be widely misunderstood, and it is as well to be sure that we are talking about exactly the same thing. I ask for the second because, other than the obvious "all the records always have the same total length", there is no universal definition of the concept, and many different ways of using something that conforms to the above obvious definition.

Thankyou.

Eric

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