Empty Element
Sometimes, the simple presence of an element is sufficient to convey meaning. That is, in some cases, you do not necessarily need information to be a Boolean, an integer, or complex type.
A simple example is the <Show Type>
element group. In this case, a slide show can be one of three types: present, browse, or kiosk. The schema for this element group is as follows:
<xsd:group name="EG_ShowType"> <xsd:choice> <xsd:element name="present" type="CT_Empty"> </xsd:element> <xsd:element name="browse" type="CT_ShowInfoBrowse"> </xsd:element> <xsd:element name="kiosk" type="CT_Empty"> </xsd:element> </xsd:choice> </xsd:group>