dtd 内部引用方式

<?xml version="1.0" encoding="utf-8"?>

<!DOCTYPE shopping [
	<!--      复合元素名称     其包含的子元素-->
	<!ELEMENT book (name,price,count)>

	<!--      简单元素名称   (#PCDATA)字符串类型-->
	<!ELEMENT name (#PCDATA)>
	<!ELEMENT price (#PCDATA)>
	<!ELEMENT count (#PCDATA)>
]>

<shopping>
	<!--购物信息 -->
	<book>
		<name>道德经</name>
		<price>100</price>
		<count>3</count>
	</book>

	<book>
		<name>论语</name>
		<price>200</price>
		<count>5</count>
	</book>

	<book>
		<name>金刚经</name>
		<price>300</price>
		<count>7</count>
		<discount>90</discount>
	</book>
</shopping>