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Re: database design method

From: Jan Hidders <hidders_at_REMOVE.THIS.uia.ua.ac.be>
Date: 11 Nov 2002 19:15:58 +0100
Message-ID: <3dcff3de$1@news.uia.ac.be>


Paul Vernon wrote:
>
>True, but would your tree tuple example be the best way of implementing a
>tree data-structure anyway?

Implementing? This is the logical level we are talking about, so a better word would be "modelling" or "representing" and it should IMO be up to the user if this is how he or she wants to represent that data that way or not.

>> >What would a valid value of Tree look like?
>> >
>> >{"NodeA:Value1", ("NodeB:Value2", ("", {}) )}
>>
>> Yeah, something like that.
>
>So
> ("", {})
>and therefore
> {}
>would be valid values of that type? Doesn't look quite right to me.

That's why I said "something like that". :-) If you want to be precise it should be for example:

  ( node-value : "book",
    subtrees : { ( node-value : "chapter1", subtrees : {} ),

                 ( node-value : "chapter2", subtrees : {} ) } )

and in this value the following nested values would also belong to the type:

   ( node-value : "chapter1", subtrees: {} )

   ( node-value : "chapter2", subtrees: {} )

Note that his example is a bit artificial because the chapters are more likely to be list then a set, but that is besides the point.

Received on Mon Nov 11 2002 - 12:15:58 CST

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