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<title>Adding a content model</title>
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<h1 class="topictitle1">Adding content models</h1>
<div><p>A content model is the representation of any data that can be contained
inside an element, global element, complex type, or group. It is a formal
description of the structure and permissible content of an element, global
element, complex type, or group, which may be used to validate a document
instance.</p>
<div class="section"><div class="p">There are three different kinds of content models:<ul><li><strong>Sequence</strong>, which means that all the content model's children can
appear in an instance of the XML schema. They must, however, appear in the
order they are listed in the content model.</li>
<li><b>Choice</b>, which means that only one of the content model's children
can appear in an instance of the XML schema.</li>
<li><b>All</b>, which means that all of the content model's children can appear
once or not at all, and they may appear in any order. If you select this option,
all of the contents model's children must be individual elements and no element
in the content model may appear more than once</li>
</ul>
</div>
<p>The following instructions were written for the Resource perspective, but 
they will also work in many other perspectives.</p>
<p>To add a content
model to an element, global element, complex type, or group, follow these
steps:</p>
</div>
<ol><li class="stepexpand"><span>In the Outline view, select your element, global element, complex
type, or group:</span><ul><li>If you selected an element or global element, you can right-click
it, and click <span class="uicontrol">Add Sequence</span>, <span class="uicontrol">Add Choice</span>,
or <b> <span class="uicontrol">Add All</span></b> to add the type of content model you want
to your element or global element. Your content model is automatically added
as a child of a local complex type - expand your element or global element
in the Outline view to see it.</li>
<li>If you selected a complex type, you can right-click it and click <b> <span class="uicontrol">Add
Sequence</span></b>, <b> <span class="uicontrol">Add Choice</span></b>, or <b> <span class="uicontrol">Add
All</span></b> to add the type of content model you want to your complex
type. Your content model is automatically added as a child of your complex
type - expand in the Outline view to see it. <b>Note: </b>These
options will not appear if you have set a base type for your complex type.
You can either set a base type for your complex type, or you add a content
model to it, but you cannot do both.</li>
<li>Your group is automatically created with a sequence content model
child. Expand it in the Outline view to see it and select it. In the Properties
view, you can select to change it to a <b> <span class="uicontrol">choice</span></b> or 
<b> <span class="uicontrol">all</span></b> content
model by selecting these options from the <b> <span class="uicontrol">Kind</span></b> drop
down list.</li>
</ul>
</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 content model must appear. If you want
the content model to be optional, select <b> <span class="uicontrol">0</span></b>. Otherwise,
select <b> <span class="uicontrol">1</span></b>. </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 a content model may appear. You
can select <span class="uicontrol">unbounded</span> to indicate there is no maximum
number of occurrences.</li>
<li class="skipspace"><span>Click the <b> <span class="uicontrol">Documentation</span></b> tab if you want
to provide any information about this content model.</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 class="skipspace"><p>You can add the following to a content object model. </p>
<ul><li>Another content model.</li>
<li>A group reference which enables the referenced group to appear in the
instance document in the context of the referencing declaration. This
menu option only appears if there are global groups defined elsewhere in the
document or if groups are defined in included schemas.</li>
<li>An element, fundamental building blocks in XML.</li>
<li>An element reference, which provides a reference to a global element.
This menu option only appears if there are global elements defined elsewhere
in the document.</li>
<li>An <samp class="codeph">any</samp> element. You can use an <samp class="codeph">any</samp> element
to extend your content model by any elements belonging to a specified namespace.</li>
</ul>
</div>
</div>
<div><div class="reltasks"><strong>Related tasks</strong><br />
<div><a href="../topics/taddanye.html" title="You can use the any element to provide something similar to a DTD's ANY content model, however, it must be done in conjunction with namespaces. This enables you to include any well-formed XML content, such as an HTML Web page that conforms to XHTML 1.0 syntax.">Adding an any element</a></div>
<div><a href="../topics/taddelm.html" title="Elements are fundamental building blocks in XML. Element declarations provide value constraints, and a description that can be used for validation, as well as establishing constraining relationships between related elements and attributes, and controlling substitution of elements.">Adding elements</a></div>
<div><a href="../topics/taddelmr.html" title="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.">Adding element references</a></div>
<div><a href="../topics/taddgrpr.html" title="A group reference is a declaration that references a group. It enables the referenced group to appear in the instance document in the context of the referencing declaration.">Adding group references</a></div>
</div>
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