How do i designate in XSD that an element only contains CDATA?

Question

How can I represent the following in XSD.

Answer 1

<element name="price-update" type="string"></element>  

is about as close as you can get.

(I thought it best to move the answer out of the comments and into an actual answer).

Answer 2

A CDATA tag is merely a means of escaping data as a text node. Therefore you cannot stipulate that you require a CDATA node.

From a DOM perspective, the following documents are identical:

<doc>value</doc>

and

<doc><![CDATA[value]]></doc>