Restriction on a Set of Elements

[dornad]

Hello everyone,I'm new at the XML Schema scene and I was wondering if someone can give me a hand with the following:I have the following structure in a xml:

<pages>	<page id="1" url="index.html" type="main">	<page id="2" url="index1.html" type="internal">	<page id="3" url="index2.html" type="catalog">	<page id="4" url="index3.html" type="product">	....</pages>

I already have the xsd with that structure and it works fine. However I need to define a set of restrictions over the elements (pages). Here is an example of some of the restrictions :

1. A main page must exist always
2. A product page can only exist if there is a catalog page.

I imagine that the others are deducible once I find out how to do the ones mentioned.Thanks

[boen_robot]

I'm sorry, but XML Schema 1.0 does not allow the existence or value of one node to determine the existence or value of another node. At least not directly. I remember reading something about abstract types here on this forum, but this required a modification in the XML file itself to include a special attribute at the element containing abstract types... or something like that... anyway, the point stands.The only thing you could do is a complete rewrite of your XML and schema into a structure that would allow that. For example:

<pages>	<main id="1" url="index.html"/>	<internal id="2" url="index1.html"/>	<catalog id="3" url="index2.html">		<product id="4" url="index3.html"/>	</catalog></pages>

With that structure, you can define a minOccurance of 1 to <main/> and define <product/> as allowed in <catalog/>. With no <catalog/>, there can't be any <product/> to place inside it.XML Schema 1.1 is aimed at fixing this while still being backwards compatible, but it's still not a recommendation and as such, it's not yet supported by any validator.