XML Structure Schema

• A simple element can only contain text; it cannot contain attributes or other elements

• An XML Structure Schema defines the following

• Elements that can appear in a document
• Attributes that can appear in a document

• Which elements are child elements
• The order of child elements
• The number of child elements

• Whether an element is empty or can include text
• Default and fixed values for elements and attributes

Compositors

• sequence: Ordered sequence of elements
• all: Unordered group of elements
• choice: A group of mutually exclusive elements or compositors