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At 10:44 AM 10/23/2005, you wrote:
Basically, I would like to develop schemas that impose
>>>constraints on an element or attribute in one XML file based on
>>>element or attribute values from another XML file. Is this at
>>>all possible? I would consider making a file containing just a
>>>list of all available item IDs, if that would help solve the
>>>problem.
>
>Theoretically, I think this could do the trick:
>
> (1) Include the XML document that contains IDs into the document that
> refers to them via a parsed external entity [XML Rec, 4.2.2, 4.3]
>
> (2) Use WXS key/keyref feature [WXS, Part 1, 3.11] to encode your
> referential constraints.
>
>(1) will physically keep the data in separate files, but the processor
>should pull them together, so the schema (2) could be written as if the
>data was present in a single file.
Let me see if I understand. The external entity could look like this:
<item id="abc123"/>
<item id="def456"/>
...
Then in some other XML document the DTD will include these lines:
<!ATTLIST item id ID #REQUIRED>
<!ENTITY itemlist SYSTEM "itemlist.xml">
and later in the body of the document:
<items>&itemlist;</items>
Something like this?
But if I am already using a DTD to describe my document, can I use a schema
as well?
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