If most of the elements in the document belong to the same namespace, it is
not necessary to prefix each element name. Instead you can define a default
namespace
that applies to all non-prefixed elements and attributes. The syntax for defining
a default namespace is xmlns=”namespace”. For example, if you define
the HR namespace as the default namespace, the document becomes easier to read:
<employees xmlns="http://www.devxpert.com/schemas/hr/"
xmlns:py="http://www.devxpert.com/schemas/payroll/">
<employee>
<id>49982</id>
<name>Bart Simpson</name>
<hireDate>2000-07-04</hireDate>
<py:salary>4000765.00</py:salary>
<py:taxes>3980765.27</py:taxes>
</employee>
<employee>
<id>12345</id>
<name>Hugo Simpson</name>
<hireDate>2000-05-29</hireDate>
<py:salary>82000.00</py:salary>
<py:taxes>16567.87</py:taxes>
</employee>
</employees>
The default namespace applies to the element on which it was defined and all
descendants of that element. If one of the descendants has another default
namespace defined on it, this new namespace definition overrides the previous
one and becomes the default for that element and all its descendants. For example,
in the following document the default namespace for the <salary> element
(and its descendants if it had any) is http://www.developerfusion.com/schemas/payroll/:
<employees xmlns="http://www.devxpert.com/schemas/hr/"
xmlns:py="http://www.devxpert.com/schemas/payroll/">
<employee>
<id>49982</id>
<name>Bart Simpson</name>
<hireDate>2000-07-04</hireDate>
<salary
xmlns="http://www.devxpert.com/schemas/payroll/”>
4000765.00
</salary>
<py:taxes>3980765.27</py:taxes>
</employee>
</employees>
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