Content types come in pairs. So while the type can be "text" and the subtype can be "pdf", the complete content type cannot be "text/pdf". It can, however, be "text/html" or "application/pdf". So in my DFDL it's not sufficient to specify enumerated lists for types and subtypes (as I have done below), I must also specify which types are allowed to go with which subtypes. How would I do that, given this complexType? TIA! <xsd:complexType name="MimeTypeType"> <xsd:sequence dfdl:separator="/"> <xsd:element name="Type" dfdl:initiator=""> <xsd:annotation> <xsd:appinfo source="http://www.ogf.org/dfdl/dfdl-1.0/"> <dfdl:assert test="{ dfdl:checkConstraints(.) }" message="The type must match one of the values on the enumerated list."/> </xsd:appinfo> </xsd:annotation> <xsd:simpleType> <xsd:restriction base="xsd:string"> <xsd:pattern value="([a|A][p|P][p|P][l|L][i|I][c|C][a|A][t|T][i|I][o|O][n|N])| ([m|M][u|U][l|L][t|T][i|I][p|P][a|A][r|R][t|T])| ([m|M][e|E][s|S][s|S][a|A][g|G][e|E])| ([t|T][e|E][x|X][t|T])" /> </xsd:restriction> </xsd:simpleType> </xsd:element> <xsd:element name="Subtype" dfdl:terminator=""> <xsd:annotation> <xsd:appinfo source="http://www.ogf.org/dfdl/dfdl-1.0/"> <dfdl:assert test="{ dfdl:checkConstraints(.) }" message="The subtype must match one of the values on the enumerated list."/> </xsd:appinfo> </xsd:annotation> <xsd:simpleType> <xsd:restriction base="xsd:string"> <xsd:pattern value="([p|P][d|D][f|F])| ([a|A][l|L][t|T][e|E][r|R][n|N][a|A][t|T][i|I][v|V][e|E])| ([m|M][i|I][x|X][e|E][d|D])| ([r|R][f|F][c|C]822)| ([p|P][l|L][a|A][i|I][n|N])| ([h|H][t|T][m|M][l|L])" /> </xsd:restriction> </xsd:simpleType> </xsd:element> </xsd:sequence> </xsd:complexType>