xsd and null string

[antobx]

Hi,
I'm working with xml string validation against xsd schema.

I'm facing this problem . This is my xml string :

<A>
<Code></Code>
</A>

<Code> value is : 'A' , 'B' or empty string ('').
'A' , 'B' in lower and upper case .

xsd element definition :
<xs:element name="Code" type="tCode" minOccurs="0" maxOccurs="1" />

My simpletype :

<xs:simpleType name="tCode">
<xs:restriction base="xs:string">
<xsattern value="((A|a)|(B|b))"/>
</xs:restriction>
</xs:simpleType>

This works fine with 'A' and 'B' . I can't validate null /empty string . What is the right definition ?
Could you help me ?
Thanks in advance .

 

[tsuji]

>I can't validate null /empty string . What is the right definition ?
Change the pattern accrodingly?
><xsattern value="((A|a)|(B|b))"/>
[tt]<xsattern value="((A|a)|(B|b))?"/>[/tt]

 

[antobx]

thankyou tsuji !


I found this too :

<xs:simpleType name="tCode">
<xs:union>
<xs:simpleType>
<xs:restriction base="xs:string">
<xsattern value="((A|a)|(B|b))"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:length value="0" />
</xs:restriction>
</xs:simpleType>
</xs:union>
</xs:simpleType>

 

[tsuji]

That can do, but it consists of a largely unnecessary twist.