Modeling with restrictions on attribute value

jacob · June 3rd, 2005, 07:01 AM

Cannot figure out how to model the folowing XML node with some further restrictions and requirements (described underneath). The node to model as XML Schema Definition...

Code:

<connections>
    <connection type="build" port="11000" />
    <connection type="admin" port="11011" />
</connections>

I want the above structure and want to model that the connection node with type build is required but the connection node with type admin is optional. Furthermore that it is only these two instances of connection which is allowed.

I have tried to model some of it in the following XML Schema Definition...

Code:

<xsd:element name="connections">
    <xsd:complexType>
        <xsd:sequence>
            <xsd:element name="connection" maxOccurs="2">
                <xsd:complexType>
                    <xsd:attribute name="type" type="connectionType" />
                    <xsd:attribute name="port" type="xsd:integer" />
                </xsd:complexType>
            </xsd:element>
        </xsd:sequence>
    </xsd:complexType>
</xsd:element>    
<xsd:simpleType name="connectionType">        
    <xsd:restriction base="xsd:string">
        <xsd:enumeration value="build"/>
        <xsd:enumeration value="admin"/>
    </xsd:restriction>
</xsd:simpleType>

However it does not specify that the connection node with type build has to appear. One node has to appear since minOccurs is 1 by default, but it might as well be the admin type.

I might add that I am not interested in renaming the connection nodes if another solution to the above is available. Should be simple to model the problem using e.g. connectionBuild and connectionAdmin.

Hope someone will help me, thanks,

Jacob.