Validate attribute names using regular expressions? - regex

Question

I would like to know if it is possible to validate attribute names by pattern using XML Schema. In other words, I would like to describe a set of acceptable attribute names for a given type, using a pattern (such as a regular expression).
Lets say I have the following XML data I would like to validate:
<?xml version="1.0" encoding="utf-8"?>
<root xmlns="http://mywebsite.com/myns">
<somename data-someattr1="value1"
data-someattr2="value2"/>
</root>
How can I describe that attributes of elements with name "somename" can only have attributes with name beginning by "data-"? Is this even possible?

Answer 1

Try something along the lines of:
<xs:simpleType name="somename">
<xs:restriction base="xs:string">
<xs:pattern value="^data-"/>
</xs:restriction>
</xs:simpleType>
The regex ^data- means "beginning with 'data-'", as you require.
EDIT:
I misunderstood the question, sorry... Here is a more relevant answer:
As I understand it, you cannot pattern match attribute names in an XSD - so there is no solution to your problem using an XSD alone. However, you may find one of the following XML schema elements helpful in constructing a solution:
XML choice (http://www.w3schools.com/schema/el_choice.asp) - so you could (possibly?) list all "data-" attribute names explicitly.
XML any (http://www.w3schools.com/schema/schema_complex_any.asp) - so you could then perform any additional validation steps via some other method.

Answer 2

Well, as it was said you can't validate attribute names, but you still can go different way and transform your xml to some kind of:
<root>
<element>
<data name='data-attr1' value='v1'/>
<data name='data-attr2' value='v2'/>
<data name='data-attr3' value='v3'/>
</element>
</root>
So now you can validate fake attribute name - data name='data-attr1' as well as values. Your schema might look like this:
<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema' elementFormDefault='qualified' attributeFormDefault='unqualified'>
<xs:element name='root'>
<xs:complexType>
<xs:sequence>
<xs:element name='element'>
<xs:complexType>
<xs:sequence>
<xs:element maxOccurs='10' name='data'>
<xs:complexType>
<xs:attribute name='name' use='required'>
<xs:simpleType>
<xs:restriction base='xs:string'>
<xs:pattern value='data-.*' />
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name='value' use='required' />
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>