namespace and targetnamespace

Can someone explain the difference between these 2? Or perhaps refer me to some document/book that explains this clearly.
Thanks

Jeff Mutonho

SCJP

targetNamespace is used in XML Schemas and WSDL to identify and select the namespace into which new elements that your are defining are created in. Once you have defined a new element you still need a namespace declaration to be able to reference the new element or type.

Example:

<?xml version="1.0" encoding="UTF-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema"
    xmlns:mh="http://www.Monson-Haefel.com/jwsbook" 
    targetNamespace="http://www.Monson-Haefel.com/jwsbook" 
    elementFormDefault="qualified">
 
    <complexType name="USAddress">
        <sequence>
            <element name="name"            type="string" />
            <element name="street"          type="string" />
            <element name="city"            type="string" />
            <element name="state"           type="string" />
            <element name="zip"             type="string" />
        </sequence>
    </complexType>
 
    <complexType name="Book">
        <sequence>
            <element name="title"           type="string" />
            <element name="quantity"        type="unsignedShort" />
            <element name="wholesale-price" type="float" />
        </sequence>
    </complexType>
 
    <complexType name="PurchaseOrder">
        <sequence>
            <element name="accountName"     type="string" />
            <element name="accountNumber"   type="unsignedShort" />
            <element name="shipAddress"     type="mh:USAddress" />
            <element name="billAddress"     type="mh:USAddress" />
            <element name="book"            type="mh:Book" />            
            <element name="total"           type="float" />            
        </sequence>
    </complexType>
 
    <element name="purchaseOrder" type="mh:PurchaseOrder" />
    <element name="address" type="mh:USAddress" />
 
</schema>

The targetNamespace is "http://www.Monson-Haefel.com/jwsbook".
Types created:

{http://www.Monson-Haefel.com/jwsbook}USAddress

{http://www.Monson-Haefel.com/jwsbook}Book

{http://www.Monson-Haefel.com/jwsbook}PurchaseOrder

Elements created:

{http://www.Monson-Haefel.com/jwsbook}purchaseOrder

{http://www.Monson-Haefel.com/jwsbook}address

Note however that there is also a namespace declaration xmlns:mh="http://www.Monson-Haefel.com/jwsbook". So when you reference anything that exists in the "http://www.Monson-Haefel.com/jwsbook" namespace you simply use the prefix "mh" within the scope of that element (in this case schema). This is used in the PurchaseOrder type definition where {http://www.Monson-Haefel.com/jwsbook}USAddress is referenced as mh:USAddress and {http://www.Monson-Haefel.com/jwsbook}Book is referenced as mh:Book.

Ronald Bourret's XML Namespaces FAQ
James Clark: XML Namespaces

Thanks.That really helped