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Don't understand this piece of XML

Answer 1

+2 A:

In Visual Studio open your xml file, go for the "XML" menu, select "Create Schema".

veljkoz 2010-08-31 23:31:40

unless, of course, he isn't a Windows programmer and doesn't have Visual Studio. ;)

Dave 2010-09-01 01:16:52

hm... I didn't thought of that :) but either way there are tons of xml tools that provide this functionality.

veljkoz 2010-09-01 09:41:39

Answer 2

+1 A:

Instead of using a group, define "Var" as an element with an "Ld" attribute:

<complexType name="Var">
    <annotation>
        <documentation>
            Description of what a Var is
        </documentation>
    </annotation>
    <attribute name="Ld" type="string">
        <annotation>
            <documentation>
                Description of what this attribute means
            </documentation>
        </annotation>
    </attribute>
</complexType>

The define the list of answers:

<complexType name="Answers">
    <annotation>
        <documentation>
            A list of Var elements
        </documentation>
    </annotation>
    <sequence>
        <element name="Var" type="Var" minOccurs="0" maxOccurs="unbounded">
            <annotation>
                <documentation>
                    The list of Var elements
                </documentation>
            </annotation>
        </element>
    </sequence>
</complexType>

Then instead of this:

<xsd:group ref="Answers"
                          minOccurs="0"
                          maxOccurs="unbounded"/>

You'd use this:

<element name="answers" type="Answers"/>

Also, a good rule of thumb is to make the default namespace match the type of file you're writing. So if you're writing a schema, put this in the root element instead and you won't have to write "xsd" prefixes everywhere:

xmlns="http://www.w3.org/2001/XMLSchema"

And it's also a good idea to create a target namespace for your schema so that your elements have an associated namespace:

targetNamespace="http://my.example.com/schema"
xmlns:mec="http://my.example.com/schema"

Which would mean your elements would be referred to as type="mec:Project" instead of just "Project" and therefore prevent any future problems when using this schema in conjunction with another one.

Gabriel 2010-09-02 19:18:35

Your answer doesn't seem to allow text inside `<var>` so it is really solves the problem only partially.

jasso 2010-09-02 23:44:40

jasso, yeah that's true, I forgot to add an element of type="string" in <var>, but you get the overall jist of it I'm sure.

Gabriel 2010-09-23 18:49:18

Answer 3

+1 A:

How to define an element to contain only text but also an attribute

Generally type of elements with only text content has to be xs:simpleType. In this case this causes a problem, because type definition of elements that can contain attributes (or other elements) must be xs:complexType. The solution is to use xs:simpleContent to allow text only and xs:extension to extend this type with the desired attributes.

Creating complex text-only elements

xs:simpleContent is used to derive types from other built-in or previously defined types. It requires either xs:extension or xs:restriction child element with attribute base that defines the base type (simple) that you will extend or restrict. In this case the base type can be xs:string. xs:extension or xs:restriction contains the desired new features.

<xs:element name="var">
    <xs:complexType>
        <xs:simpleContent>
            <xs:extension base="xs:string">
                <xs:attribute name="Ld" type="xs:string" />
            </xs:extension>
        </xs:simpleContent>
    </xs:complexType>
</xs:element>

Several attribute definitions can added inside xs:extension - in this case we only needed one. xs:simpleContent cannot contain any element definitions, only new attributes. If the base type is not the same as any of the built-in schema datatypes, for example if the text has some length restrictions, you must define the base type as a global simple type definition and use its name in the base attribute.

Allowing text inside elements that can contain other elements is simpler: just use <xs:complexType mixed="true"> when defining the element contents.

jasso 2010-09-02 23:11:03

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Don't understand this piece of XML

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How to define an element to contain only text but also an attribute

Creating complex text-only elements

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