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Re: Create recursive data models! Top-down data models arebori

• From: Dimitre Novatchev <dnovatchev@gmail.com>
• To: "Costello, Roger L." <costello@mitre.org>
• Date: Thu, 29 Jan 2015 10:34:21 -0800

Maybe designing a naturally-recursive structure (like a "tree") would
be a better example?

There is no alternative to a recursive model for a recursive data structure.

-- 
Cheers,
Dimitre Novatchev


On Thu, Jan 29, 2015 at 9:07 AM, Costello, Roger L. <costello@mitre.org> wrote:
> Hi Folks,
>
> Question: What does JSON, XML Schema, and XSLT have in common?
>
> Answer: they are all recursively defined; they specify a set of components which can be assembled in dazzlingly many ways.
>
> Conversely, many (I dare say most) data designs are created in top-down fashion with a mindless list of data. For example, consider a data model for Books. The top-down approach is to mindlessly reel off properties about Books: Title, Author, Genre, etc. Then create instances like this:
>
> <Book>
>     <Title>Parsing Techniques</Title>
>     <Author>Dick Grune</Author>
>     <Genre>Technical</Genre>
> </Book>
>
> Boring.
>
> Not only boring, it is clumsy and lacking in power. To wit: instead of that arrangement of the pieces of data, suppose I want this arrangement:
>
> <Title>
>     <Value>Parsing Techniques</Value>
>     <Author>Dick Grune</Author>
>     <Genre>Technical</Genre>
> </Title>
>
> Moreover, I want my Book data model to contain pieces that can be assembled in arbitrarily different ways - I want a recursive data model!
>
> How might we create a recursive data model for Book data? Here's one way:
>
> Book -> (Title | Author | Genre)+
>
> Title -> Value, Book?
>
> Author -> Value, Book?
>
> Genre -> Value, Book?
>
> That is a massively recursive data model. And it is way cool.
>
> My new slogan: Just say "No!" to top-down data models and say "Yes!" to recursive data models.
>
> Comments?
>
> /Roger
>
>
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• References:
  • Create recursive data models! Top-down data models are boring andlacking in power
    • From: "Costello, Roger L." <costello@mitre.org>