- From: Kevin Burges <xmldude@burieddreams.com>
- Date: Mon, 19 Nov 2001 12:50:49 +0000
- To: ht@cogsci.ed.ac.uk ((Henry S. Thompson))
- CC: xmlschema-dev@w3.org
>> <Check FormIDRef="FORM_2" FieldIDRef="FIELD_1"/>
>>
>> I need to check in this case that FIELD_1 exists within FORM_2.
>>
>> Are you saying I cannot do this at present? I thought that was the
>> point of having multiple <field xpath=""> elements?
HST> The point of that is to identify something that has a multipart key.
HST> Your Field doesn't have it's own multipart key, it has a cascaded or
HST> multi-stage key -- first find Form with this key, then find Field with
HST> _this_ key. That's what's not supported yet, sorry.
I *think* I understand what you're saying here but maybe not because
it still seems to me that I should be able to do what I want, at least
in part.
I understand that a single key cannot assert the uniqueness of FormIDs
and FieldIDs within those, as that would be a multi-stage key. Lets
assume this uniqueness does not exist, and something like this was valid:
<IDs>
<Form FormID="FORM_1">
<Field FieldID="FIELD_1"/>
</Form>
<Form FormID="FORM_2">
<Field FieldID="FIELD_1"/>
</Form>
<Form FormID="FORM_1"> <!-- NOTE: FORM_1 again -->
<Field FieldID="FIELD_2"/>
</Form>
</IDs>
Could I not have a multipart key which consists of:
{@FormID @FieldID}
which in this example would give:
{FORM_1 FIELD_1}
{FORM_2 FIELD_1}
{FORM_1 FIELD_2}
By my understanding this would be a multipart key not a multi-stage
key, because it is only the combination of FormID and FieldID which is
being constrained.
Functionally it would do what I want, as I could set a keyref to check
that:
<Check FormID="FORM_1" FieldID="FIELD_2"/>
does actually refer to the {FORM_1 FIELD_2} entry in of the key??
--
groovy baby,
Kevin mailto:xmldude@burieddreams.com
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Received on Monday, 19 November 2001 07:51:07 UTC