Title: Re: [ubl-lcsc] RE: [ubl-ndrsc] Functional Dependency and Normalization paper
Burcham, Bill wrote:
> I guess I should explain my issue with DTD now. It isn't DTD per se, as
> much as it is global element declarations that are the problem. UBL doesn't
> use global element declarations (much), so examples that use them end up
> specifying structures that differ in important ways (from UBL ones).
>
> The particular flavor of the differences plays heck with e.g. our whole
> container debate. The main issue is that there is no way using element
> declarations to support reuse of an element in two different content models
> without incurring an extra level of container.
Indeed you can do this kind of modeling using entities. Here's a DTD
that will allow both RejectedOrderitem and AcceptedOrderItem with a
common content model and no surrounding container :
<?xml version="1.0"?>
<!DOCTYPE ubl [
<!ENTITY % order.basic.content "(item, quantity)">
<!ELEMENT ubl (RejectedOrderItem*|AcceptedOrderItem*)>
<!ELEMENT item (#PCDATA)>
<!ELEMENT quantity (#PCDATA)>
<!ELEMENT order %order.basic.content;>
<!ELEMENT RejectedOrderItem (%order.basic.content;, error)>
<!ELEMENT error (#PCDATA)>
<!ELEMENT AcceptedOrderItem (%order.basic.content;, status)>
<!ELEMENT status (#PCDATA)>
]>
This document is then valid :
<?xml version="1.0"?>
<!DOCTYPE ubl SYSTEM "ubl.dtd">
<ubl>
<RejectedOrderItem>
<item>..</item>
<quantity>...</quantity>
<error>...</error>
</RejectedOrderItem>
<AcceptedOrderItem>
<item>..</item>
<quantity>...</quantity>
<status>...</status>
</AcceptedOrderItem>
</ubl>
Thus you can see that by using massively entity declaration (even for
PCDATA content) you can control your global elements with a DTD.
Note that however I'm not advocating the use of DTDs for UBL ;-)
Fabrice
--
Fabrice Desré - FT.BD/FTR&D/DTL/TAL
Tél: (33) 2 96 05 31 43
Fax: (33) 2 96 05 39 45
