XML Namespaces

1. XML Namespaces • Each schema file associated with a URL to uniquely identify where elements come from • Like packages in Java http://www.ebay.com http://www.amazon.com http://www.superstore.ca

2. TargetNamesapce • So, if I’m writing a schema for my superstore <schema ... targetNamespace=“http://www.superstore.com” >

3. Label prefixes • Instead of referring to URLs, namespaces are given short prefix labels <schema ... targetNamespace=“http://www.superstore.ca” xmlns:ebay=http://www.ebay.com > <element name=“eBayProduct” ref=“ebay:Product” /> </schema>

4. Referring to XML Schema schema • XML Schema is an XML language itself with a schema. <xs:schema targetNamespace=“http://www.superstore.ca” xmlns:ebay=http://www.ebay.com” xmlns:xs=“http://www.w3.org/2001/XMLSchema” > <xs:element name=“eBayProduct” type=“ebay:Product”/> </xs:schema>

5. Default Namespace • One namespace can be given no label, for convenience <schema ... targetNamespace=“http://www.superstore.ca” xmlns:ebay=http://www.ebay.com” xmlns=“http://www.w3.org/2001/XMLSchema” > <element name=“eBayProduct” type=“ebay:Product”/> </schema>

6. Declarations • Prefixes are not used when declaring names of elements or types • Prefixes are used when referring to elements or types <schema ... targetNamespace=“http://www.superstore.ca” xmlns:ebay=http://www.ebay.com” xmlns=“http://www.w3.org/2001/XMLSchema” > <element name=“eBayProduct” type=“ebay:Product”/> </schema>