Re: Merging two documents

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 99/09/20 19:02 -0700, Terris wrote:
> Do you think using document() is superior to
> concatenating the two documents first?

Absolutely!

> For example, the following XML document
> would be created:
>
> <ConcatenatedDocument>
>
>   <DocumentA>
>     <Book id="1"><Name>The wizard of OZ</Name></Book>
>     <Book id="2"><Name>Java Servlet Programming</Name></Book>
>     <Book id="3"><Name>John Coltrane Rage</Name></Book>
>   </DocumentA>
>
>   <DocumentB>
>     <BookList>
>       <Book id="1"/>
>       <Book id="2"/>
>    </BookList>
>   </DocumentB>
>
> </ConcatenatedDocument>

In your specific example above there would probably be no problems, but 
what if both documents had attributes declared as ID attributes?

What if there were an element in each document that happened by coincidence 
to have the same unique identifier?

Using document() allows you to still access both documents, but access the 
unique identifiers found in both documents without the risk of 
collision.  My examples earlier showed how using <xsl:for-each> with the 
document() function allows you to access the ID space within each document 
independently.

If both documents, each with the same ID in use, were merged into one, it 
couldn't be validated (because of duplicate IDs) and the id() function of 
XSLT would at best only find one and at worst report the duplicate ID as an 
error and refuse to execute.

Of course this isn't a problem if you aren't using IDs, but I assumed you 
were asking about the general case.

I hope this helps.

............ Ken


--
G. Ken Holman                    mailto:gkholman@xxxxxxxxxxxxxxxxxxxx
Crane Softwrights Ltd.             http://www.CraneSoftwrights.com/s/
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                             1999-12-07, 2000-02-27/28, 2000-05-11/12



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