The document discusses the building blocks of XML documents including elements, attributes, entities, PCDATA, and CDATA. It also covers how each component is declared in a DTD including element declarations, attribute declarations, and restrictions on content and occurrence.
19. Attribute-type The value is a predefined xml value xml: The value is a name of a notation NOTATION The value is a list of entities ENTITIES The value is an entity ENTITY The value is a list of valid XML names NMTOKENS The value is a valid XML name NMTOKEN The value is a list of other ids IDREFS The value is the id of another element IDREF The value is a unique id ID The value must be one from an enumerated list ( en1 | en2 |..) The value is character data CDATA Description Type
20. Default value The default-value can be one of the following: The attribute value is fixed #FIXED value The attribute is not required #IMPLIED The attribute is required #REQUIRED The default value of the attribute value Explanation Value