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Re: [xml-dev] Is it good/useful to normalize an XML data exchange format?

I agree.  Normalizing any data used for query (read) is counter productive.  Data should be optimized for the fastest read possible.  Also, normalizing the data will complicate if not destroy the ability of machine read transfers (if we are talking at the element level.). I have no issues with transporting PK, BK or NK keys as attributes of an element.

Daniel L. Koger
Enterprise Architect
Sent from my iPad

On Nov 24, 2014, at 1:15 PM, Peter Hunsberger <peter.hunsberger@gmail.com> wrote:

The decision on whether to normalize or not is made in response to the space / time constraints surrounding the implementation.  If space is the primary constraint you normalize, if time is the primary constraint you don't.

On Mon Nov 24 2014 at 11:00:01 AM Costello, Roger L. <costello@mitre.org> wrote:

Hi Folks,

 

First, what is normalization? Answer: it is removing redundancy.

 

For example, in the following XML document the element <Author>Dick Grune</Author> occurs twice:

 

<BookCatalogue>
   
<Book>
       
<Title>Parsing Techniques</Title>
       
<Author>Dick Grune</Author>
   
</Book>
   
<Book>
       
<Title>Modern Compiler Design</Title>
       
<Author>Dick Grune</Author>
   
</Book>
</BookCatalogue>

 

Normalizing the XML document means eliminating the redundancy, perhaps like so:

 

<BookCatalogue>
   
<BooksByAuthor author="Dick Grune">
       
<Title>Parsing Techniques</Title>
       
<Title>Modern Compiler Design</Title>
   
</BooksByAuthor>
</BookCatalogue>

 

Across the Internet chatter we often hear people proclaim:

 

<image003.png>

 

After all, a key part of designing database tables is to put them in “Normal Form”.

 

With all that normalization hype everyone then assumes that everything needs to be normalized. However, that is not correct.

 

The benefit of normalizing only applies when adding/deleting/modifying data. When the data is read-only (as is the case with a data exchange format) there is no benefit to normalizing. In fact, normalizing is the worst thing that you can do. Consider this: read-only databases are typically not normalized, they contain lots of redundant data so as to optimize read operations.

 

Should a data exchange format be normalized? Answer: No!

 

Comments?

 

/Roger



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