xml-dev - How to avoid empty elements

[David Valera <dvalera@pcl-hage.nl>]

hello,

I have defined a simple type like this:

<xsd:element name="Header">
	<xsd:simpleType base="xsd:string">
		<xsd:pattern value="[a-z]{15, 25}"/>
	</xsd:simpleType>
</xsd:element>

My understanding was that this pattern would only allow strings that match
the value. But if I try to validate this:

<Header></Header>

then it validates ok.

Is the empty string always allowed, no matter wich pattern value you have?
Is this a bug in my validator software or am I missing something? according
to the XML schema part 2:

S{n,m} = All strings st with s in L(S) and t in L(S{n-1,m-1}). ( All
sequences of at least n, and at most m, strings from L(S) )

and S? = the empty string, and all strings in L(S).


TIA
David Valera