docs/org.eclipse.wst.xmleditor.doc.user/topics/txsityp.dita

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<task id="txsityp" xml:lang="en-us">
<title>Using xsi:type</title>
<titlealts>
<searchtitle>Using xsi:type</searchtitle>
</titlealts>
<shortdesc>If you have elements in your XML file whose type is a complex type,
xsi:type support in the XML editor lets you choose between the complex type
and any other complex types derived from it.</shortdesc>
<taskbody>
<context><p>The XML Schema specification allows you to derive types by extension.
See the following steps as an example<?Pub Caret?>:</p></context>
<steps>
<step><cmd>Create an XML schema and create a complex type for it called  <userinput>Address</userinput>. </cmd>
</step>
<step><cmd>Add some basic elements to <userinput>Address</userinput>, such
as <userinput>streetName</userinput> and <userinput>city</userinput>.</cmd>
</step>
<step><cmd>Derive (by extension) two new complex types from <userinput>Address</userinput>: <userinput>USAddress</userinput> and <userinput>UKAddress</userinput
>. </cmd></step>
<step><cmd>Add a new element to <userinput>USAddress</userinput> called  <userinput>state</userinput>,
and also a new element to <userinput>UKAddress</userinput> called <userinput>postcode</userinput>.</cmd>
</step>
<step><cmd>Create two more elements: <userinput>billTo</userinput> and <userinput>shipTo</userinput>,
as  <systemoutput>Address</systemoutput> types.</cmd></step>
<step><cmd>When you create an XML instance document for an element such as
 <systemoutput>billTo</systemoutput> or  <userinput>Address</userinput>, an
xsi:type attribute will automatically be added to it.</cmd><info>For example, <codeblock>&lt;billTo xsi:type="ipo:Address"></codeblock>The
xsi:type attribute is used to identify derived complex types (as well as complex
types that have been derived from).</info></step>
<step><cmd>In the Design view of the XML editor, a list will be available,
letting you select the appropriate type definition (<uicontrol>Address</uicontrol>, <uicontrol>USAddress</uicontrol>,
or  <uicontrol>UKAddress</uicontrol>). The guided editing for the content
model will reflect the type definition that you choose. For example, if you
select  <uicontrol>USAddress</uicontrol> , your <codeph>billTo</codeph> element
can contain a <codeph>state</codeph> element, but it cannot contain a <codeph>postcode</codeph> element.</cmd>
</step>
</steps>
<postreq><p>The XML example "Editing and validating XML files" demonstrates <b>xsi:type</b> support.</p><p>For
more information about xsi:type, refer to the <b>Using Derived Types in Instance
Documents</b> section in <xref format="html" href="http://www.w3.org/TR/xmlschema-0/#UseDerivInInstDocs"
scope="external">XML Schema Part 0: Primer.</xref></p><p>For more information
about validation semantics when xsi:type is used, refer to the <b>Schema-Related
Markup in Documents Being Validated</b> section in  <xref format="html" href="http://www.w3.org/TR/xmlschema-1/#xsi_type"
scope="external">XML Schema Part 1: Structures</xref> </p></postreq>
</taskbody>
</task>
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