Please quote what you're replying to.

Kai Schlamp <stroncococcus@g...> wrote in
<1193913218.460782.168360@o...>:
> I just want to scheme a simple xml tag like this
> <mytag myattr="10">foo</mytag>
> and want to restrict "foo" to the length of 10 characters,
> thats all. But I didn't find an example on the web for
> doing such an restriction in this case (I am pretty new to
> XML, but I think you already know that ;-))
> As I understand the mytag must be a complex type, cause it
> has an attribute ("myattr") and a content ("foo").
> What's the best way to achieve this?

Well, restrict then extend.

pavel@debian:~/dev/schema$ a schema.xsd
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="textarea" type="textareaType"/>
  <xs:attribute name="label" type="xs:string"/>
  <xs:complexType name="textareaType">
    <xs:simpleContent>
      <xs:extension base="str-10-chr">
        <xs:attribute ref="label" use="required"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
  <xs:simpleType name="str-10-chr">
    <xs:restriction base="xs:string">
      <xs:maxLength value="10"/>
    </xs:restriction>
  </xs:simpleType>
</xs:schema>
pavel@debian:~/dev/schema$ for F in sch*.xml ; do
xmllint --schema schema.xsd $F ; echo ; done
<?xml version="1.0"?>
<textarea>more than 10 characters</textarea>
sch1.xml:1: element textarea: Schemas validity error :
Element 'textarea': The attribute 'label' is required but
missing.
sch1.xml:1: element textarea: Schemas validity error :
Element 'textarea': [facet 'maxLength'] The value has a
length of '23'; this exceeds the allowed maximum length
of '10'.
sch1.xml:1: element textarea: Schemas validity error :
Element 'textarea': 'more than 10 characters' is not a
valid value of the atomic type 'str-10-chr'.
sch1.xml fails to validate

<?xml version="1.0"?>
<textarea label="aaa">more than 10 characters</textarea>
sch2.xml:1: element textarea: Schemas validity error :
Element 'textarea': [facet 'maxLength'] The value has a
length of '23'; this exceeds the allowed maximum length
of '10'.
sch2.xml:1: element textarea: Schemas validity error :
Element 'textarea': 'more than 10 characters' is not a
valid value of the atomic type 'str-10-chr'.
sch2.xml fails to validate

<?xml version="1.0"?>
<textarea>&lt;10 chars</textarea>
sch3.xml:1: element textarea: Schemas validity error :
Element 'textarea': The attribute 'label' is required but
missing.
sch3.xml fails to validate

<?xml version="1.0"?>
<textarea label="aaa">&lt;10 chars</textarea>
sch4.xml validates

pavel@debian:~/dev/schema$

I heartily recommend reading W3C's XML Schema Primer. It
might take you a day or two, but will give you a solid
understanding of the basics.

-- 
"I can't help but wonder if you... don't know a hell of a
lot more about practically every subject than Solomon ever
did."