Creating an XML document from the XML schema
In this section we shall create an XML document instance, catalog.xml (which was listed in the introduction), from the registered schema catalog.xsd. We're using a registered schema, but it is not essential as it's also possible to create an XML document instance using an XML schema in the file system.
However, using a registered XML schema does have an advantage. You may associate it with a specific file extension. For example, to register an XML schema for generating only .xslt files you would associate the .xslt extension with the XML schema.
Select project node XMLSchema in Application Navigator, and select File|New. In the New Gallery window select Categories|General|XML. Select XML Document from XML schema in the Items listed. Click on the OK button.
The Create XML Document from XML schema wizard gets started. Click on the Next button.
In the File Location window specify the XML File name as catalog.xml. Select Use Registered Schemas to create an XML document from a registered schema. Click on the Next button.
In the Options window select Root Element as catalog. Any of the global elements in a registered XML schema may be selected as the root element. To create an XML document from an XML schema fragment select another global element as the root element. If you want to generate XML document fragments, specify element constructs in an XML schema using the global element declarations and refer to the elements within a complexType using the ref attribute. The other options that may be specified are the Depth of the XML document to be generated in terms of element levels, encoding, and the option to Generate Only Required Elements. Click on the Next button.
In the Finish window, click on the Finish button. An XML document, catalog.xml, instance gets added to the Application Navigator. The XML document has all of the elements defined in the XML schema from which the XML document is instantiated. The default document created has a single instance of elements defined with cardinality greater than 1 in the XML schema. For example, only one instance of the journal element is added by default in the XML document instantiated from catalog.xsd. Additional journal elements may be added as required. If a choice is defined in the XML schema, the default XML document generated has the first of the elements specified in the choice.
Next, we shall add element and attribute values to the XML schema to construct the XML document catalog.xml. Select the journal node in the Structure view. In the Property Inspector specify values for the attributes title, publisher, and edition.
Select the article element node in the Structure view and specify the value for the section attribute and the title and author elements in the Property Inspector.
To add another journal element, right-click on the catalog node in the Structure view and select Insert inside catalog|journal.
A <journal/> node gets added to the catalog element.
Select the journal node in the Structure view and add values for title, publisher, and edition attributes in the Property Inspector.
Next, add an article element node to the journal element. In the Structure view, right-click on the journal node and select Insert inside journal|article.
In the Insert article window, specify values for author and title elements. Click on the OK button.
In Property Inspector specify a value for the section attribute. The section attribute was not in the Insert article window because it is an optional attribute.
A journal element including the attributes and subelements gets added to the catalog.xml document.
A registered schema also supports editing the XML in the source editor with code help. The complete XML document, catalog.xml, instantiated from the XML schema catalog.xsd is shown in the following illustration:
