Check constraints can be used…

<xsd:annotation>
<xsd:appinfo source="http://www.ogf.org/dfdl/dfdl-1.0/">
<dfdl:assert test="{ dfdl:checkConstraints(.) }" message="There cannot be more than 59 seconds in a minute."/>
</xsd:appinfo>
</xsd:annotation>

…to validate (while parsing) the restrictions placed on an element:

<xsd:simpleType>
<xsd:restriction base="xsd:unsignedInt">
<xsd:maxInclusive value="59"/>
</xsd:restriction>
</xsd:simpleType>

Is check constraints similarly required to validate the fixed value of an element while parsing?

<xsd:element name="MimeVersion" dfdl:initiator="MIME-Version:%SP;" dfdl:terminator="%NL;" type="xsd:string" dfdl:length="3" dfdl:lengthKind="explicit" fixed="1.0">

If not, then how do I force it to validate while parsing?

TIA