RE: Purpose of <xs:sequence/>

 

It is in some XML Schemas that we have been given to work with from a
supplier. I believe that these were originally generated from a UML
modelling tool called Enterprise Architect.

 

 

Thanks Adam.

 

________________________________

From: Koray SAKIROGLU [mailto:koray.sakiroglu@gmail.com] 
Sent: 19 June 2008 13:53
To: Adam Retter
Subject: Re: Purpose of <xs:sequence/>

 

Where did you see such declaration of <xs:sequence/> ?

Was it in a xsd file editor-generated from a xml file ? 



2008/6/19 Adam Retter <Adam.Retter@landmarkinfo.co.uk>:


Hi Chaps,

I am having trouble understanding what the purpose of an empty sequence
declaration is?

e.g. - <xs:sequence/> or <xsd:sequence/>

Certainly it seems to have no relevance in a document instance of that
Schema.

For example in one of the Schemas here we have global declarations like
this -

<xs:element name="Classifier" type="Classifier"/>
<xs:complexType name="Classifier">
       <xs:sequence/>
       <xs:attribute name="pid" type="xs:string" use="required"/>
</xs:complexType>


In this case it's probably to avoid possible error if someone were to
complete the schema and add the sequence [b]after[/b] the attribute
(call it declaration etiquette).
 

	
	<xs:element name="Reference" type="Reference"/>
	<xs:complexType name="Reference">
	       <xs:sequence/>
	</xs:complexType>


No idea, this is basicaly a tag without content or attribute, it could
as well have been a simple element, maybe the creator is planning to
complete his element later on and decided to make it complex ?

All in all, I see no real point to such declaration, much could depend
on where you saw such declaration, maybe an erroned/out of date editor?
 

	
	
	There is probably some design subtlety that I am missing, can
someone
	explain it?
	
	Thanks
	
	Adam Retter
	
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