Question

I am having a bit of a problem with empty values failing validation on one server, but it works on all my other servers. The problem occurs on a newer PHP version (5.3.8) and works on a slightly older version (5.2.4).

Here are a couple of isolated elements which fail:

XML Input:

<clbburnfuelbias></clbburnfuelbias>
<clbburntimebias></clbburntimebias>

XSD Validation:

  <xs:element name="clbburnfuelbias"  type="data-fuelbias"/>
  <xs:element name="clbburntimebias"  type="data-timebias"/>

  <xs:simpleType name="data-fuelbias">
    <xs:restriction base="xs:integer">
      <xs:minInclusive value="-9900"/>
      <xs:maxInclusive value="9900"/>
    </xs:restriction>
  </xs:simpleType>
  <xs:simpleType name="data-timebias">
    <xs:restriction base="xs:integer">
      <xs:minInclusive value="-59"/>
      <xs:maxInclusive value="59"/>
    </xs:restriction>
  </xs:simpleType>

Error:

Error 1824: Element ‘clbburnfuelbias’: The value is not a valid value
of the atomic type ‘data-fuelbias’. Error 1824: Element
‘clbburntimebias’: The value is not a valid value of the atomic type
‘data-timebias’.

Using the exact same input and XSD files on different servers running 5.2.4 I get no errors and the xml is valid.

I have tried adding minOccurs=”0″ to the elements, I have tried specifying nullable=”true” as well but still get the errors.

UPDATE:

It appears that null values are ignored on my servers using PHP 5.2.4, and rejected using 5.3.8. A work around that I’ve used which was suggested is to use a union of two definitions, one for the integer type, and one for a null value:

XSD:

<xs:element name="clbburnfuelbias" minOccurs="0">
  <xs:simpleType>
    <xs:union memberTypes="data-fuelbias null-string"/>
  </xs:simpleType>
</xs:element>

<xs:simpleType name="data-fuelbias">
  <xs:restriction base="xs:integer">
    <xs:minInclusive value="-9900"/>
    <xs:maxInclusive value="9900"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType name="null-string">
  <xs:restriction base="xs:string">
    <xs:length value="0"/>
  </xs:restriction>
</xs:simpleType>

Answer 1

Making an element optional (minOccurs="0") doesn’t make its contents a wildcard. If the element appears, it must match the declared type.

Making an element nillable (nillable="true") allows the element to be empty if it has the xsi:nil="true" attribute, where xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance":

<clbburnfuelbias xsi:nil="true"></clbburnfuelbias>
<clbburntimebias xsi:nil="true"></clbburntimebias>

You may also use a union type, which only has the same meaning for validation purposes:

<xs:simpleType name="data-fuelbias">
  <xs:union>
    <xs:restriction base="xs:integer">
      <xs:minInclusive value="-9900"/>
      <xs:maxInclusive value="9900"/>
    </xs:restriction>
    <xs:restriction base="xs:string">
      <xs:length value="0"/>
    </xs:restriction>
  </xs:union>
</xs:simpleType>