Restrict XSD attribute value based on another attribute value

Question

I have this in the XML:

<Const Name="a" Value="1.0"/>
<Const Name="b" Value="1"/>
<Const Name="c" Value="A"/>
<Const Name="d" Value="B"/>

I have these two cases:

• For a Const element with Name="b" the Value must be one of 1, 2, 3 or 4. No other values are allowed.
• Other Const elements may contain other values, as shown.

How do I express that in XSD?

So far I have this:

<xs:element name="Const">
   <xs:complexType>
       <xs:attribute name="Value" type="xs:string" use="required"/>
       <xs:attribute name="Name" type="xs:string" use="required"/>
   </xs:complexType>
</xs:element>

I use XSD 1.0, it seems: VS2013... so "Alternative" does not work for me... sadly...

Answer 1

You can do this using XSD 1.1's Conditional Type Assignment:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
  xmlns:vc="http://www.w3.org/2007/XMLSchema-versioning"
  elementFormDefault="qualified"
  vc:minVersion="1.1"> 

  <xs:element name="Const">
    <xs:alternative test="@Name = 'a'" type="aType"/>        
    <xs:alternative                    type="otherType"/>
  </xs:element>

  <xs:complexType name="aType">
    <xs:sequence/>
      <xs:attribute name="Name" type="xs:string"/>
      <xs:attribute name="Value">
        <xs:simpleType>
          <xs:restriction base="xs:integer">
            <xs:minInclusive value="1"/>
            <xs:maxInclusive value="4"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
  </xs:complexType>

  <xs:complexType name="otherType">
    <xs:sequence/>
    <xs:attribute name="Name" type="xs:string"/>
    <xs:attribute name="Value" type="xs:string"/>
  </xs:complexType>
</xs:schema>