Re: XSD Regular Expressions and empty content

Hi Chris,

this can be acheived using xs:union to join two (or more) simple types
together.
Normally a truly empty type is created using an empty complexType but this
cannot be used in a union AFAIK

The schema snippet below is a union of your date type with an empty string
type.

<xs:element name="date" type="ESimpleDateType"/>
<xs:simpleType name="ESimpleDateType">
<xs:union memberTypes="SimpleDateType empty"/>
</xs:simpleType>

<xs:simpleType name="SimpleDateType">
<xs:restriction base="xs:integer">
<xsattern value="[0-9]{8}"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="empty">
<xs:restriction base="xs:string">
<xs:maxLength value="0"/>
</xs:restriction>
</xs:simpleType>

This seems to validate <date>12345678</date> and <date></date> and even
<date/> (in MSXML 4 and XMLSpy)

There may be a better way but I cant think of it for the moment.

P.S. why are you using your own date type rather than the built in types?
Your type will allow a dates including
20030626 and
26032003 not to mention
20039999 and
99992003

Colin

"Chris West" <> wrote in message
news:bdh0r9$gnv$...
> I want to restrict the content of an elements by declaring them of the
> following type:
>
> <xsd:simpleType name="SimpleDateType">
> <xsd:restriction base="xsd:integer">
> <xsdattern value="[0-9]{8"/>
> </xsd:restriction>
> </xsd:simpleType>
>
> but I also want to allow empty content in xml instances, without using the
> "nillable" attribute. Any suggestions?
>
> Thanks
>
> Chris
>
>

Colin Mackenzie