either/or elements in xml schema

Discussion in 'XML' started by inquirydog, Aug 9, 2004.

  1. inquirydog

    inquirydog Guest

    I am trying to store my computer network information in an xml file,
    and plan to write an xml schema for the file. The general format of
    the xml should be like this

    <networkinfo>
    <ipaddress>1.2.3.4</ipaddress>
    <hostname>qwerty</hostname>
    <dnsserver>7.7.7.7</dnsserver>
    </networkinfo>

    The xml schema for this is simple (so simple that I won't
    mention it). The problem is that on some computers, the network
    information should be determined by dhcp, and all of the usual
    information is not needed. In these cases the xml should look like
    this

    <networkinfo>
    <dhcp />
    </networkinfo>

    I don't know how to write an xml schema that requires either n
    elements (ie- ipaddress, hostname, and dnsserver), or a single
    different element (ie- dhcp). I could bin the n elements in another,
    and then use xsd:choice, although it seems a waste to add another tag
    for this reason only.

    I thank anyone in advance for suggestions.

    thank
    -I

    ps- extra credit if you can extend this to describe an arbitrary
    number of ethernet cards (eth0 ipaddress, eth1 ipaddress, etc.)
     
    inquirydog, Aug 9, 2004
    #1
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  2. "inquirydog" <> schrieb im Newsbeitrag
    news:...
    > I am trying to store my computer network information in an xml file,
    > and plan to write an xml schema for the file. The general format of
    > the xml should be like this
    >
    > <networkinfo>
    > <ipaddress>1.2.3.4</ipaddress>
    > <hostname>qwerty</hostname>
    > <dnsserver>7.7.7.7</dnsserver>
    > </networkinfo>
    >
    > The xml schema for this is simple (so simple that I won't
    > mention it). The problem is that on some computers, the network
    > information should be determined by dhcp, and all of the usual
    > information is not needed. In these cases the xml should look like
    > this
    >
    > <networkinfo>
    > <dhcp />
    > </networkinfo>
    >
    > I don't know how to write an xml schema that requires either n
    > elements (ie- ipaddress, hostname, and dnsserver), or a single
    > different element (ie- dhcp). I could bin the n elements in another,
    > and then use xsd:choice, although it seems a waste to add another tag
    > for this reason only.
    >
    > I thank anyone in advance for suggestions.
    >
    > thank
    > -I
    >
    > ps- extra credit if you can extend this to describe an arbitrary
    > number of ethernet cards (eth0 ipaddress, eth1 ipaddress, etc.)


    Hi

    as I understand the problem this should be a solution

    The Schema:

    <xs:schema elementFormDefault="qualified" attributeFormDefault="unqualified"
    xmlns:xs="http://www.w3.org/2001/XMLSchema">

    <xs:element name="networkinfo" type="info"/>

    <xs:complexType name="info" abstract="true"/>

    <xs:complexType name="standardinfo">
    <xs:complexContent>
    <xs:extension base="info">
    <xs:sequence>
    <xs:element name="ipadress" type="xs:string"/>
    <xs:element name="hostname" type="xs:string"/>
    <xs:element name="dnsserver" type="xs:string"/>
    </xs:sequence>
    </xs:extension>
    </xs:complexContent>
    </xs:complexType>

    <xs:complexType name="dhcpinfo">
    <xs:complexContent>
    <xs:extension base="info">
    <xs:sequence>
    <xs:element name="dhcp" type="xs:string"/>
    </xs:sequence>
    </xs:extension>
    </xs:complexContent>
    </xs:complexType>
    </xs:schema>

    and a sampleinstance

    <networkinfo xsi:type="standardinfo">
    <ipadress/>
    <hostname/>
    <dnsserver/>
    </networkinfo>

    note that the schema uses three types: an abract info type and two types
    (standardinfo and dhcpinfo) that extend the abstract type. the only element
    is of typ info. For the instance document this means that you have replace
    the type of the element by one of the none abstact subtypes. (with the
    xsi:type attribute). An Instance of dhcpinfo would look like:

    <networkinfo xsi:type="dhcpinfo">
    <dhcp/>
    </networkinfo>

    greetings

    hd
     
    Helmut Dirtinger, Aug 9, 2004
    #2
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  3. Hi,

    You could also do something simpler using xsd:choice, like:

    <xs:element name="networkinfo" type="info"/>
    <xs:complexType name="info">
    <xs:choice>
    <xs:sequence>
    <xs:element name="ipadress" type="xs:string"/>
    <xs:element name="hostname" type="xs:string"/>
    <xs:element name="dnsserver" type="xs:string"/>
    </xs:sequence>
    <xs:element name="dhcp" type="xs:string"/>
    </xs:choice>
    </xs:complexType>

    Hope that helps,
    Priscilla
    -----------------------------------------------------
    Priscilla Walmsley
    Author, Definitive XML Schema (Prentice Hall PTR)
    http://www.datypic.com
    -----------------------------------------------------

    *** Sent via Developersdex http://www.developersdex.com ***
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    Priscilla Walmsley, Aug 9, 2004
    #3
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