I need to create xml schema where all the nodes <foo> must contain either one or more occurance of <c1> only or one occurance of <c2> only as follows.
<main>
<foo>
<a></a>
<b></b>
<c1></c1>
</foo>
<foo>
<a></a>
<b></b>
<c1></c1>
</foo>
<foo>
<a></a>
<b></b>
<c1></c1>
</foo>
</main>
or
<main>
<foo>
<a></a>
<b></b>
<c2></c2>
</foo>
<foo>
<a></a>
<b></b>
<c2></c2>
</foo>
<foo>
<a></a>
<b></b>
<c2></c2>
</foo>
</main>
Can anyone help me?
When you have an "either - or" situation, your solution is usually <xs:choice>. Use maxOccurs and minOccurs attributes to restrict how many times element can appear. Default value for those attributes is "1" which is used if you don't add those attributes.
A sample code snippet for the definition of the <foo> element. Note the usage of <xs:choice> and maxOccurs="unbounded"
<xs:element name="foo">
<xs:complexType>
<xs:sequence>
<xs:element name="a" type="xs:string />
<xs:element name="b" type="xs:string />
<xs:choice>
<xs:element name="c1" maxOccurs="unbounded" type="xs:string />
<xs:element name="c2" type="xs:string />
</xs:choice>
</xs:sequence>
</xs:complexType>
</xs:element>
Related
My new XML private language includes elements <figure>, representing illustrations (image + caption).
Whenever illustrations refer to some image in the local database I just want to type
<figure id="9809" width="full" />
to identify image number 9809 and its associated caption.
On the other side, if images come from outside I will need a slightly different syntax:
<figure href="https://some-url-here" width="full">Some ad hoc catpion</figure>
So far I have declared an element that combine both behaviours, like this:
<!-- Figures -->
<xs:simpleType name="FigureWidthEnum">
<xs:restriction base="xs:token">
<xs:enumeration value="center" />
<xs:enumeration value="half" />
<xs:enumeration value="full" />
</xs:restriction>
</xs:simpleType>
<xs:element name="figure">
<xs:complexType mixed="true">
<xs:complexContent>
<xs:extension base="Inline">
<xs:attribute name="href" type="URI" />
<xs:attribute name="id" type="xs:nonNegativeInteger" />
<xs:attribute name="width" type="FigureWidthEnum" default="full" />
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
It works fine but a fresh editor can mess with the 3 attributes and type impossible things I don't want to pass the Schema Validator that easy. For example:
<figure id="9809" width="full" href="https://some-unexpected-url">Some unexpected caption that should not be here</figure>
I want to have two completely separate sintaxes for <figure>, as if I could declare these two elements with the same name:
<xs:element name="figure">
<xs:complexType mixed="true">
<xs:complexContent>
<xs:extension base="Inline">
<xs:attribute name="href" type="URI" />
<xs:attribute name="width" type="FigureWidthEnum" default="full" />
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:element>
<xs:element name="figure">
<xs:complexType>
<xs:attribute name="id" type="xs:nonNegativeInteger" />
<xs:attribute name="width" type="FigureWidthEnum" default="full" />
</xs:complexType>
</xs:element>
In fact it is not possible.
Can it be done somehow?
Yes, it is possible with XSD 1.1, which provides <xs:alternative> element intended specifically for such requirements. Here's a complete XML schema I've designed to validate exactly as you need:
<?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"
vc:minVersion="1.1">
<!-- Figures -->
<xs:simpleType name="FigureWidthEnum">
<xs:restriction base="xs:token">
<xs:enumeration value="center" />
<xs:enumeration value="half" />
<xs:enumeration value="full" />
</xs:restriction>
</xs:simpleType>
<!-- stub definition -->
<xs:complexType name="Inline"/>
<!-- 'figure' element is declared once, but its type has two alternatives -->
<xs:element name="figure">
<!-- The first alternative is selected, when the condition specified
in 'test' attribute is true. The condition must be a boolean XPath
expression. The '#id' returns the value of 'id' attribute. However,
when converted to boolean, it indicates whether 'id' attribute is
specified at all. The anonymous complexType inside <xs:alternative>
provides the element type valid for this case.
-->
<xs:alternative test="#id">
<xs:complexType>
<xs:attribute name="id" type="xs:nonNegativeInteger" />
<xs:attribute name="width" type="FigureWidthEnum" default="full" />
</xs:complexType>
</xs:alternative>
<!-- The second alternative has no 'test' attribute. That means, it must
be selected by default, when all other alternatives (with a specified
test condition) do not pass. Here, the anonymous complexType inside
<xs:alternative> defines the element type in case of reference:
when 'href' is present.
-->
<xs:alternative>
<xs:complexType mixed="true">
<xs:complexContent>
<xs:extension base="Inline">
<xs:attribute name="href" type="xs:anyURI" />
<xs:attribute name="width" type="FigureWidthEnum" default="full" />
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:alternative>
</xs:element>
<!-- this element is defined just to test the whole schema in XML below -->
<xs:element name="figures">
<xs:complexType>
<xs:sequence>
<xs:element ref="figure" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
A complete XML file this schema validates:
<?xml version="1.0" encoding="UTF-8"?>
<figures>
<!-- passes validation -->
<figure id="9809" width="full" />
<!-- passes validation -->
<figure width="full" href="https://some-unexpected-url">Some ad hoc caption</figure>
<!-- does not pass the validation -->
<figure id="9809" width="full" href="https://some-unexpected-url">
Some unexpected caption that should not be here
</figure>
</figures>
The validation was done with Apache Xerces 2.11.0 (XSD 1.1 aware).
Promo add-on. These links may be interesting for those working with XML schemas and WSDL: FlexDoc/XML XSDDoc & WSDLDoc – High-performance universal XML Schema / WSDL Documentation Generators with Diagrams
My system parses two XML files (via JAXB unmarshalling and xjc generated code)
componentModel.xml : generated from a modeling tool
detailedDesign.xml : manual, to add informations
In order to avoid to code checks upon content and structures, each file is validated with its own XSD
componentModel.xsd
detailedDesign.xsd
Both of these xsd inclulde "utilities.xsd" where common complex and simple types are defined
All works well
I now want to add consistency check :
unicity of Ids (names of components)
components in "detailsDesign" must refers one of the components in "componentModel" via the "name" and "nameRef" attributes
Here are the structures (i've simlplified names and structures in files to show only relevant informations)
Note : as you can see, i don't use any namespace except the default one
componentModel.xml
<?xml version="1.0" encoding="UTF-8"?>
<componentModel>
<components>
<component name="id1"> ... </component>
<component name="id1"> ... </component>
<component name="id2"> ... </component>
</components>
</componentModel>
componentModel.xsd
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" >
<xs:include schemaLocation="utilities.xsd" />
<xs:complexType name="CMComponent">
<xs:complexContent>
...
<xs:attribute name="name" type="MUUpperFirstName" use="required" />
</xs:complexContent>
</xs:complexType>
<xs:complexType name="CMComponents">
<xs:sequence>
<xs:element name="component" type="CMComponent" minOccurs="0" maxOccurs="unbounded" />
</xs:sequence>
</xs:complexType>
<xs:complexType name="CMComponentModel">
<xs:complexContent>
<xs:sequence>
<xs:element name="components" type="CMComponents">
<!-- Key used to check "name" unicity and as a ref by nameRef attribute in detailedDesign model -->
<xs:key name="componentNameKey">
<xs:selector xpath="component" />
<xs:field xpath="#name" />
</xs:key>
</xs:element>
<xs:element name="functionalChains" minOccurs="0" maxOccurs="1" />
</xs:sequence>
<xs:attribute name="name" type="MUModelName" use="required" />
</xs:complexContent>
</xs:complexType>
<xs:element name="componentModel" type="CMComponentModel" />
</xs:schema>
utilities.xsd
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:simpleType name="MUString">
<xs:restriction base="xs:string"/>
</xs:simpleType>
<xs:simpleType name="MUUpperFirstName">
<xs:restriction base="MUString">
<xs:pattern value="([A-Z]+[a-zA-Z0-9]*[.])*[A-Z]+[a-zA-Z0-9]*"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="MUReferenceName">
<xs:restriction base="MUString">
<xs:pattern value="([A-Z]+[a-zA-Z0-9]*[.])*[a-zA-Z]+[a-zA-Z0-9]*"/>
</xs:restriction>
</xs:simpleType>
</xs:schema>
detailedDesign.xml
<?xml version="1.0" encoding="UTF-8"?>
<detailedDesignModel>
<components>
<component nameRef="id1"> ... </component>
<component nameRef="id2"> ... </component>
<component nameRef="id3"> ... </component>
</components>
</detailedDesignModel>
detailedDesign.xsd
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:include schemaLocation="utilities.xsd" />
<xs:include schemaLocation="componentModel.xsd" />
<xs:complexType name="DDMComponent">
<xs:complexContent>
...
<xs:attribute name="nameRef" type="MUReferenceName" use="required" />
</xs:complexContent>
</xs:complexType>
<xs:complexType name="DDMComponents">
<xs:sequence>
<xs:element name="component" type="DDMComponent" minOccurs="0" maxOccurs="unbounded" />
</xs:sequence>
</xs:complexType>
<xs:complexType name="DDMDetailDesignModel">
<xs:complexContent>
<xs:sequence>
<xs:element name="components" type="DDMComponents">
<xs:keyref name="componentNameKeyRef" refer="componentNameKey">
<xs:selector xpath="component" />
<xs:field xpath="#nameRef" />
</xs:keyref>
</xs:element>
</xs:sequence>
</xs:complexContent>
</xs:complexType>
<xs:element name="detailDesignModel" type="DDMDetailDesignModel" />
</xs:schema>
It works for unicity of 'name' attribute among components (error retrieved from ValidationEventHandler set on unmarshaller) :
Duplicate key value [id1] declared for identity constraint of element "components".
But i can't get the "keyref" functionnality working (error retrieved from ValidationEventHandler set on unmarshaller) :
Identity Constraint error: identity constraint "KeyRef#272ed83b" has a keyref which refers to a key or unique that is out of scope.
How can i make the keyRef to see the Key defined in the orther XSD file
Thanks
Matth
I have just made my first attempt at XSD.
When I try and validate my XML against my XSD, I get the error:
Cannot find the declaration of element 'linkage'.
Below I give my XSD and a cut down version of my XML. I've tried adding a namespace qualifier to the top element in my XML and also to every element (changing the XSD to qualified) and it did not help. I'm obviously making a basic mistake. As I'm new to XSD, if you could include what I need to change in my XML and/or XSD I would be very grateful.
XSD:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://www.stephenwaring.me.uk/android/nestedsettings"
xmlns="http://www.stephenwaring.me.uk/android/nestedsettings"
elementFormDefault="unqualified">
<xs:element name="linkage">
<xs:complexType>
<xs:sequence>
<xs:element name="preference-screen" maxOccurs="unbounded">
<xs:complexType>
<xs:sequence>
<xs:element name="parent" maxOccurs="unbounded">
<xs:complexType>
<xs:sequence>
<xs:element name="child" maxOccurs="unbounded">
<xs:complexType>
<xs:attribute name="key" type="xs:token" use="required" />
<xs:attribute name="reformat" type="xs:boolean" />
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attributeGroup ref="keyed" />
<xs:attribute name="preference-screen" type="xs:token" use="required" />
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attributeGroup ref="keyed"/>
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:attributeGroup ref="defaults"/>
</xs:complexType>
</xs:element>
<xs:attributeGroup name="defaults">
<xs:attribute name="html" type="xs:boolean" />
<xs:attribute name="prefix" type="xs:string" />
<xs:attribute name="suffix" type="xs:string" />
<xs:attribute name="separator" type="xs:string"/>
<xs:attribute name="reformat" type="xs:boolean" />
<xs:attribute name="shaddow" type="xs:boolean" />
<xs:attribute name="child-summary" type="xs:boolean" />
<xs:attribute name="shadow-separator" type="xs:string"/>
</xs:attributeGroup>
<xs:attributeGroup name="keyed">
<xs:attributeGroup ref="defaults" />
<xs:attribute name="key" type="xs:token" use="required" />
</xs:attributeGroup>
</xs:schema>
Cut down XML:
<?xml version="1.0" encoding="UTF-8"?>
<linkage
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://stevewaring.me.uk/android/nestedsettings nestedsettings.xsd"
xmlns="http://www.stevewaring.me.uk">
<preference-screen
key="preferences1">
<parent
key="prefFruit"
preference-screen="preferences2">
<child key="prefFruit1"/>
<child key="prefFruit2"/>
</parent>
</preference-screen>
</linkage>
Your XSD defines elements in http://www.stephenwaring.me.uk/android/nestedsettings whereas your document element is in http://www.stevewaring.me.uk. Make them to agree, one way or the other, and it should take care of the error you're having.
I've added a fixed XML, there's another issue related to use of unqualified elements.
<?xml version="1.0" encoding="UTF-8"?>
<linkage xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.stephenwaring.me.uk/android/nestedsettings nestedsettings.xsd" xmlns="http://www.stephenwaring.me.uk/android/nestedsettings">
<preference-screen xmlns="" key="preferences1">
<parent key="prefFruit" preference-screen="preferences2">
<child key="prefFruit1"/>
<child key="prefFruit2"/>
</parent>
</preference-screen>
</linkage>
For the following xml need a schema.
<?xml version="1.0" encoding="UTF-8"?>
<overall_operation>
<operation type="list_products">
<ops_description>Listing all the products of a company</ops_description>
<module>powesystem</module>
<comp_name>APC</comp_name>
<prod_price>50K$</prod_price>
<manf_date>2001</manf_date>
<pool_name>Electrical</pool_name>
<fail_retry>2</fail_retry>
<storage_type>avialble</storage_type>
<storage_check>false</storage_check>
<api_type>sync</api_type>
<product_name>transformer</product_name>
</operation>
<operation type="search_product">
<ops_description>Search the products of a company from the repository</ops_description>
<module>high-voltage</module>
<module>powesystem</module>
<comp_name>APC</comp_name>
<pool_name>Electrical</pool_name>
<fail_retry>2</fail_retry>
<storage_type>avialble</storage_type>
<storage_check>false</storage_check>
<api_type>sync</api_type>
<product_name>setup-transformer</product_name>
</operation>
</overall_operation>
Here different elements with operation like list_products,search_products and so on.
Each element will have some common attributes such as ops_description,module and so on.
Also some of the unique attributes for each element such as prod_price,manf_date etc.
I want to have a xml schema to validate. Some of the attributes also optional.
I tried using abstract and derived but could not make it work.
What you want to achieve is not possible with xml schema. The definition states that every element or attribute must be validated on its own and without reference to other elements or attributes.
The best solution you can get is to group optional but dependent elements:
<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="overall_operation">
<xs:complexType>
<xs:sequence>
<xs:element name="operation" minOccurs="0" maxOccurs="unbounded">
<xs:complexType>
<xs:sequence>
<xs:element name="ops_description" />
<xs:element name="module" minOccurs="1" maxOccurs="2" />
<xs:element name="comp_name" />
<xs:group ref="price_and_date" minOccurs="0" maxOccurs="1" />
<xs:element name="pool_name" />
<xs:element name="fail_retry" />
<xs:element name="storage_type" />
<xs:element name="storage_check" />
<xs:element name="api_type" />
<xs:element name="product_name" />
</xs:sequence>
<xs:attribute name="type" type="xs:string" />
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:group name="price_and_date">
<xs:sequence>
<xs:element name="prod_price" />
<xs:element name="manf_date" />
</xs:sequence>
</xs:group>
</xs:schema>
Use minOccurs and maxOccurs attributes to control optional elements and groups.
I have following piece of XML:
<items>
<item type="simple">some text</item>
<item type="complex"><b>other text</b></item>
</items>
I can define the "item" element with DTD, as:
<!ELEMENT item (#PCDATA|b)*>
How can I define it with XML Schema(XSD)?
XML schemas have these swell abstract types that make this thing pretty easy as long as having the xsi prefix on the type attribute in your actual XML doesn't bother you. You can define what you have above as follows:
<!--items element-->
<xs:element name="items">
<xs:complexType>
<xs:sequence>
<xs:element ref="item" maxOccurs="unbounded" />
</xs:sequence>
</xs:complexType>
</xs:element>
<!--individual item element-->
<xs:element name="item" type="item" />
<!--make the item type abstract so you're forced to declare its type in the XML file-->
<xs:complexType name="item" abstract="true" />
<!--declare your simple type - mixed content is so that you can have text in a complex type-->
<xs:complexType name="simple">
<xs:complexContent mixed="true">
<xs:extension base="item">
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!--declare your complex type-->
<xs:complexType name="complex">
<xs:complexContent>
<xs:extension base="item">
<!--define the stuff that can go into that complex element-->
<xs:sequence>
<xs:element name="b" type="xs:string" />
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
And your resulting XML would be as follows:
<items xmlns="your-namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<item xsi:type="simple">some text</item>
<item xsi:type="complex">
<b>other text</b>
</item>
</items>