Groups

There are three group elements: choice, sequence, and all.

group element

The <group> element groups a set of element declarations so that they can be incorporated into complex type definitions. The <group> element is limited to the top level of the content model.

choice element

The <choice> element allows one and only one of the elements contained in the group to be present within the containing element.

sequence element

The <sequence> element requires the element in the group to appear in the specified sequence within the containing element.

all element

The <all> element allows the elements in the group to appear (or not appear) in any order in the containing element.