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| <reference id="rrefintg" xml:lang="en-us"> | |
| <title>Referential integrity in the XML schema editor</title> | |
| <titlealts> | |
| <searchtitle>Referential integrity</searchtitle> | |
| </titlealts> | |
| <shortdesc>The XML schema editor has a built-in mechanism to handle referential | |
| integrity issues. When you delete certain nodes, clean up for any nodes affected | |
| will automatically occur.</shortdesc> | |
| <prolog><metadata> | |
| <keywords><indexterm>XML schema editor<indexterm>referential integrity</indexterm></indexterm> | |
| <indexterm>XML schema editor<indexterm>clean up in</indexterm></indexterm> | |
| </keywords> | |
| </metadata></prolog> | |
| <refbody> | |
| <section>When you define a complex type, you can add a content model to it | |
| and reference a global element. <p>For example:<codeblock><schema> | |
| <element name="comment" type="string"> | |
| <complexType name="Items"> | |
| <sequence> | |
| <element ref="comment"> | |
| </sequence> | |
| </complexType> | |
| </schema></codeblock></p><p>If the global element (comment) was deleted, | |
| all references to it would be in error. However, when you delete the global | |
| element, the XML schema editor will clean up using the following algorithm:</p><ul> | |
| <li>If there are one or more global elements in the schema, it will change | |
| all existing references to the first global element.</li> | |
| <li>If there is no global element, then it will delete the element reference | |
| from the content model.</li> | |
| </ul></section> | |
| <section><title>Deleting included and imported schema</title><p>If an included | |
| or imported schema is deleted, you must manually reset the following type | |
| references as appropriate: <ul> | |
| <li>Global element and element's type</li> | |
| <li>Attribute type</li> | |
| <li>Complex type derivation</li> | |
| <li>Simple type derivation </li> | |
| </ul>They will not automatically be reset if an included or imported schema | |
| is deleted.</p></section> | |
| </refbody> | |
| </reference> |