Constraint References
The attribute group AG_ConstraintRefAttributes defines the attributes used to specify a constraint reference. The attribute group is defined as:
<xsd:attributeGroup name="AG_ConstraintRefAttributes"> <xsd:attribute name="refType" type="ST_ConstraintType" use="optional" default="unknown" /> <xsd:attribute name="refFor" type="ST_ConstraintRelationship" use="optional" default="self" /> <xsd:attribute name="refForName" type="xsd:IDREF" use="optional" /> <xsd:attribute name="refPtType" type="ST_ElementType" use="optional" default="all" /> </xsd:attributeGroup>