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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> |
| </div> |
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