January 2003
Beginner to intermediate
1200 pages
23h 42m
English
As discussed in the beginning of the chapter, entities can be either internal or external. We already saw how to create an internal general reference in the beginning of the chapter, when we created an internal general entity named TODAY and referenced it as &TODAY; in the document:
<?xml version = "1.0" standalone="yes"?>
<!DOCTYPE DOCUMENT [
<!ELEMENT DOCUMENT (CUSTOMER)*>
<!ELEMENT CUSTOMER (NAME,DATE,ORDERS)>
<!ELEMENT NAME (LAST_NAME,FIRST_NAME)>
<!ELEMENT LAST_NAME (#PCDATA)>
<!ELEMENT FIRST_NAME (#PCDATA)>
<!ELEMENT DATE (#PCDATA)>
<!ELEMENT ORDERS (ITEM)*>
<!ELEMENT ITEM (PRODUCT,NUMBER,PRICE)>
<!ELEMENT PRODUCT (#PCDATA)>
<!ELEMENT NUMBER (#PCDATA)>
<!ELEMENT PRICE (#PCDATA)>
<!ENTITY TODAY "October ...