- From: <paul.downey@bt.com>
- Date: Mon, 30 Jan 2006 13:55:04 -0000
- To: <public-xsd-databinding@w3.org>, <edday@obj-sys.com>
Hi Ed, > But this reminds me of another binding issue. There is (apparently) no > equivalent in XSD to the ASN.1 NULL type. The result is that users have to > make up their own and the results are often inconsistent. For example, in > the CSTA specs, we see the following type definition: > <xsd:annotation> > <xsd:documentation>replacement for ASN.1 NULL type and helper type for > representation of the ASN.1 BIT STRING type</xsd:documentation> > </xsd:annotation> > <xsd:complexType name="Empty"/> I notice that ITU-T Rec. X.694 (01/2004) suggests this pattern: http://www.itu.int/ITU-T/studygroups/com17/languages/X694pdf > In XMPP, there is: > > <xs:simpleType name='empty'> > <xs:restriction base='xs:string'> > <xs:enumeration value=''/> > </xs:restriction> > </xs:simpleType> > It would be nice if a best practice schema pattern for representing empty > data could be published. I suggest we add 'Null datatype" to our roadmap and offer both of these as possible Schema patterns currently in the wild. Paul
Received on Monday, 30 January 2006 13:55:23 UTC