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<title>Adding an element reference</title>
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<h1 class="topictitle1">Adding element references</h1>
<div><p>An element reference provides a reference to a global element. A 
	declaration that references a global element enables the referenced global 
element to appear in the instance document in the context of the referencing
declaration.</p>
<div class="section"><p>You can modify the contents of your global element directly via
an element reference. For example, you can add attributes and attribute reference
to an element reference, but they are actually being added to your global
element.</p>
The menu option to add an element reference only appears if there
are global elements defined elsewhere in the document.<p>The following instructions
were written for the Resource perspective, but they will also work in many
other perspectives.</p>
<p>To add an element reference, follow these
steps:</p>
</div>
<ol><li class="skipspace"><span>In the Outline view, right-click the content model you want to
work with and click <b> <span class="uicontrol">Add Element Ref</span>.</b></span></li>
<li class="skipspace"><span>Select the element reference.</span></li>
<li class="skipspace"><span>In the Properties view, select the global element you want to reference
in the <span class="uicontrol">ref</span> list.</span></li>
<li class="skipspace"><span>(Optional) Select the appropriate value in the <b> <span class="uicontrol">MinOccurs</span></b> field.</span> This is the number of times the global element referenced may appear.
If you want the element to be optional, select <span class="uicontrol">0</span>. Otherwise,
select <span class="uicontrol">1</span>. </li>
<li class="skipspace"><span>(Optional) Select the appropriate value in the <b> <span class="uicontrol">MaxOccurs</span></b> field.</span> This is the maximum number of times the global element referenced may
appear. You can select <span class="uicontrol">unbounded</span> to indicate there
is no maximum number of occurrences.</li>
<li class="stepexpand"><span>(Optional) Click the <b> <span class="uicontrol">Other</span></b> tab.</span> In
this page, you can specify the following various values for the global element
you are referencing: <ul><li><b><span class="uicontrol">abstract</span></b>. Click <strong>true </strong>if you want the
global element to be abstract. When a global element is declared to be abstract,
it cannot be used in an instance document. Instead, a member of that global
element's substitution group must appear in the instance document.</li>
<li><b><span class="uicontrol">block</span></b>. This field determines whether the global
element may be replaced by an element derived from it.</li>
<li><b><span class="uicontrol">final</span></b>. This field determines whether this global
element may be derived from.</li>
<li><b><span class="uicontrol">fixed/default</span>.</b> Click the <b> <span class="uicontrol">More</span></b> button
and select the <b> <span class="uicontrol">Fixed</span></b> or <b> <span class="uicontrol">Default</span></b> radio
button and specify an appropriate value. If you select <strong>Fixed</strong>, the global
element has a fixed value, which cannot be changed. If you select <strong>Default</strong>,
the element has a default value.</li>
<li><b><span class="uicontrol">form</span></b>. Use this field to indicate if the appearance
of this global element in an instance of the XML schema (that is, an XML file
associated with the XML schema) must be qualified by a namespace.</li>
<li><b><span class="uicontrol">nillable</span></b>. Select <strong>true</strong> if you do not
want the global element to be able to have any child elements, only attributes. </li>
<li><b><span class="uicontrol">substitutionGroup</span></b>. A substitution group allows
elements to be substituted for other elements.</li>
</ul>
</li>
<li class="skipspace"><span>Click the <b> <span class="uicontrol">Attributes</span></b> tab.</span> You
can use this page to add attributes, attribute references, attributes group
references, and <samp class="codeph">any</samp> attributes to your element reference.</li>
<li class="skipspace"><span>An attribute associates an attribute name with a specific type
and value. To add an attribute, right-click in the Attributes page, and click <b> <span class="uicontrol">Add
Attribute</span></b>.</span> You can specify the following values for
an attribute<ul><li><b><span class="uicontrol">fixed/default</span>.</b> Click the
	<b> <span class="uicontrol">More</span></b> button
	<img border="0" src="../images/More.gif" width="22" height="18"> and select the
	<b> <span class="uicontrol">Fixed</span></b> or <b> <span class="uicontrol">Default</span></b> radio
button and specify an appropriate value. If you select <b>Fixed</b>, the attribute
has a fixed value, which cannot be changed. If you select <b>Default</b>,
the attribute has a default value.</li>
<li><b><span class="uicontrol">form</span></b>. Use this field to indicate if the appearance
of this attribute in an instance of the XML schema must be qualified by a
namespace.</li>
<li><b><span class="uicontrol">name</span></b>. Enter the name of the attribute.</li>
<li><b><span class="uicontrol">type</span></b>. Click the <span class="uicontrol">More</span> button
and select the type of the attribute. </li>
<li><b><span class="uicontrol">use</span></b>. This field indicates how an attribute
may be used in an instance document. If you select <b>optional</b>, the attribute
may appear once, but it does not have to. If you select <b>required</b>, the
attribute must appear once. If you select <b>prohibited</b>, the attribute
must not appear. <b>Note</b>: If you selected the <b> <span class="uicontrol">Default</span></b> radio
button, you must select <b>optional</b> in this field, otherwise the default
value will not be valid.</li>
</ul>
</li>
<li class="skipspace"><span>An attribute reference provides a reference to a global attribute.
To add an attribute reference, right-click in the Attributes page, and click <b> <span class="uicontrol">Add
Attribute Ref</span>.</b></span> A declaration that references a global
attribute enables the referenced attribute to appear in the instance document
in the context of the referencing declaration. The menu option to add
an attribute reference only appears if there are global attributes defined
elsewhere in the document.<ol type="a"><li><span>Select the reference, then select the global attribute you want
it to reference from the <b> <span class="uicontrol">ref</span> </b>drop down list.</span></li>
</ol>
</li>
<li class="skipspace"><span>An attribute group reference provides a reference to an attribute
group. To add an attribute group reference, right-click in the Attributes
page, and click <b> <span class="uicontrol">Add Attribute Group Ref</span></b>.</span> A
declaration that references an attribute group enables the referenced attribute
group to appear in the instance document in the context of the referencing
declaration. The menu option to add an attribute group reference only appears
if there are attribute groups defined elsewhere in the document.<ol type="a"><li><span>Select the reference, then select the attribute group you want
it to reference from the <b> <span class="uicontrol">ref</span></b> drop down list.</span></li>
</ol>
</li>
<li class="stepexpand"><span>An <samp class="codeph">any</samp> element enables element content according
to namespaces, and the corresponding <samp class="codeph">any</samp> attribute element
enables attributes to appear in elements. To add an <samp class="codeph">any</samp> attribute,
right-click in the Attributes page and click<b> <span class="uicontrol">Add Any Attribute</span>.</b></span> You can specify the following values for an <samp class="codeph">any</samp> attribute:<ul><li>For a <strong>namespace</strong> value, you can select <strong>##any</strong> (this allows
any well-formed XML from any namespace), <b>##local </b> (this allows any
well-formed XML that is not declared to be in a namespace, <b>##other </b> (this
allows any well-formed XML that is not from the target namespace of the type
being defined) or <b>##targetNamespace </b> (which is shorthand for the target
namespace of the type being defined). </li>
<li>For a <b> <span class="uicontrol">processContents</span></b> value, you can select <b>skip</b> (the
XML processor will not validate the attribute content at all), <b>lax </b>(the
XML processor will validate the attribute content as much as it can), or <b>strict </b> (the
XML processor will validate all the attribute content).</li>
</ul>
 </li>
<li class="skipspace"><span>Click the <b> <span class="uicontrol">Documentation</span></b> tab if you want
to provide any information about this element reference.</span> The <span class="uicontrol">Documentation</span> page is used for human readable
material, such as a description, and the <span class="uicontrol">App Info</span> 
page can be used to provide information for applications.</li>
</ol>
</div>

<div><p><b class="reltaskshd">Related tasks</b><br />
<a href="../topics/taddglem.html" title="A global element is an element with a global scope. It is one that has been declared as part of the main schema rather than as part of a complex type definition.">Adding a global element</a><br />
</p>
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