Oxygen XML Forum

Posted: **Tue Jul 27, 2004 1:45 am**

I was not sure if I should post this to Problems or Feature Requests, so I am trying here first.

Here is the sample

    <xs:simpleType name="TimeType">

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

            <xs:length value="6"/>

            <xs:minLength value="6"/>

            <xs:maxLength value="6"/>

            <xs:pattern value="[0-2][0-3][0-5][0-9][0-5][0-9]"/>

        </xs:restriction>

    </xs:simpleType>

XML-Spy says this is valid.
oXygen says "It is an error for both length and either of minLength or maxLength to be specified."

I found errata here (http://www.w3.org/2001/05/xmlschema-errata#e2-66) that says that it is OK to do it this way.

How do we proceed from here ?

Posted: **Tue Jul 27, 2004 2:34 am**

Hi Dan,

The erata specifies two conditions linked by and for each of the maxLength and minLength facets:

If length is a member of {facets} then
1 It is an error for minLength to be a member of {facets} unless
1.1 the {value} of minLength <= the {value} of length and
1.2 there is type definition from which this one is derived by one or more restriction steps in which minLength has the same {value} and length is not specified.
2 It is an error for maxLength to be a member of {facets} unless
2.1 the {value} of length <= the {value} of maxLength and
2.2 there is type definition from which this one is derived by one or more restriction steps in which maxLength has the same {value} and length is not specified.

Your schema does not fulfill the second condition (1.2 and 2.2, respectively) as the base type is xs:string which does not have the minLength or the maxLength facet defined, therefore it is invalid.

I think the erata allows something like:

Code: Select all


  <xs:simpleType name="TimeTypeBase">

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

      <xs:minLength value="6"/>

      <xs:maxLength value="6"/>

    </xs:restriction>

  </xs:simpleType>

  

  <xs:simpleType name="TimeType">

    <xs:restriction base="TimeTypeBase">

      <xs:length value="6"/>

      <xs:pattern value="[0-2][0-3][0-5][0-9][0-5][0-9]"/>

    </xs:restriction>

  </xs:simpleType>

which is successfully validated by Oxygen.
Oxygen uses the latest Xerces release (2.6.2) to perform XML schema validation.

Best Regards,
George

Posted: **Tue Jul 27, 2004 2:43 am**

OK, the errata is convoluted, but I think I get it.

Bottom line is that you cannot have length/minLength/maxLength all in the same group, yes ?

I will direct a polite grouch at the XML-Spy folks

Thank you for the clarification.

Posted: **Tue Jul 27, 2004 2:45 am**

Actually, it is good to know that oXygen uses Xerces. I plan to use the C++ Xerces library to work with the schemas I am making.

This adds one more great reason not to spend US$500 on the pro version of XML Spy

Thanks again.

Posted: **Tue Jul 27, 2004 3:00 am**

I think yes, there is no point to define a maxLength or a minLength together with length, this will be redundant. However, if a base type specifies a maxLength it makes sense to restrict that to the maximum specified length value in a derived type by restriction.

Oxygen uses the Java version of Xerces, Xerces J. Anyway some of the Xerces J developers are among the Xerces C developers so they should be quite similar.

Best Regards,
George

Posted: **Tue Jul 27, 2004 3:46 pm**

Seems like overkill, doesn't it ?

Perhap the intent was to say, for a string field of length 6, that there must be exactly 6 characters, no more, no less.

But then I would expect saying (minLength=6 maxLength=6) would do that.

Just my opinion. I could be wrong.

Thanks again for the clarification.

Oxygen XML Forum

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