The types element encloses data type definitions that are relevant for the exchanged messages. For maximum interoperability and platform neutrality, WSDL prefers the use of XSD as the canonical type system, and treats it as the intrinsic type system.

Code:

<definitions name="StockQuote" 
		targetNamespace="http://example.com/stockquote.wsdl" 
		xmlns:tns="http://example.com/stockquote.wsdl" 
		xmlns:xsd1="http://example.com/stockquote.xsd" 
		xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" 
		xmlns="http://schemas.xmlsoap.org/wsdl/">
	<types>
		<schema targetNamespace="http://example.com/stockquote.xsd"
				xmlns="http://www.w3.org/2000/10/XMLSchema"> 
			<element name="SubscribeToQuotes">
				<complexType>
					<all>
						<element name="tickerSymbol" type="string"/> 
					</all>
				</complexType> 
			</element>
			<element name="SubscriptionHeader" type="uriReference"/> 
		</schema>
	</types> 
</definitions>

Reversed UML model: