Attributes v Elements

["Conder, Tom D (N-MAXIM Group)" <tom.d.conder@lmco.com>]

Is there a good reference on the Web offering advice about various design
decisions I have to make while developing a DTD (or XMLSchema)?

For example, it is not immediately obvious when to use attributes and when
to make an element a complex type.

Suppose we want to make an XML file whose structure supports currency. Which
is better?

1) a simple type with an attribute

	<currency type="USDollar">
	   10
	</currency>

2) a complex type with no attribute

	<currency>
	   <type>USDollar</type>
	   <value>10</value>
	</currency>

3) a simple type with two attributes

	<currency type="USDollar" value="10"/>

Is there a simple rule of thumb to apply to the use of attributes?

Tom Conder - Contractor, Lockheed Martin Mission Systems
1035 Eastgate Drive
O'Fallon IL 62269
(618) 628-2051