restriction of an Element which can be empty

[Jens U]

Hi,

I do Need to restrict an xs:element like the following:

<xs:restriction base="xs:string">

<xs:pattern value="[0-9]{9}"></xs:pattern>

</xs:restriction>

But I have to allow, that it is may empty.

The following is not working:

<xs:restriction base="xs:string">

<xs:pattern value="[0-9]{0|9}"></xs:pattern>

</xs:restriction>

[Ingolme]

This pattern should work: ([0-9]{9})?