XML Schema documents can be edited in Text View, Grid View, and Schema View. The default view in which XML Schema documents open can be set in the File Types section of the Options dialog. You can switch between views while you edit, using the view that is most useful for the current purpose. XML Schema documents are typically saved with the extension .xsd or .xs.
Editing in Text View
In Text View an XML Schema is edited as an XML document; the editing features available for XML documents are also available for XML Schemas. As with all XML documents where the schema is identified and accessible, Text View entry helpers display the items available for addition at the cursor location point.
Editing in Grid View
In Grid View an XML Schema is edited as an XML document; the editing features available for XML documents are also available for XML Schemas. When an item in Grid View is selected, Grid View entry helpers display the items available for addition at the cursor location point.
Editing in Schema View
Schema View is a graphical interface for designing schemas. While you create/edit the schema in Schema View, XMLSpy generates a corresponding text document behind the interface. How to create and edit XML Schema documents in Schema View is described in detail in the section Editing Views | Schema View.
Altova website: XML Schema Editor
XML Schema features in XMLSpy
Additionally, XMLSpy offers the following very useful features:
•Convert XML Schema to DTD: With the DTD/Schema | Convert Schema to DTD command, XML Schemas can be converted to DTDs.
•Generate sample XML file from XML Schema: With the DTD/Schema | Generate Sample XML File command, an XML document can be generated that is based on the active XML Schema. Sample values can also be specified for elements and attributes in the sample XML.