Namespaces and Property Names

Topic Last Modified: 2006-06-11

It is recommended that property names for Exchange store items be composed of a Uniform Resource Identifier (URI) and a local name. The URI portion of the property name ensures that it is globally unique and unambiguous. Two properties with the same local name can therefore be differentiated by using the namespace.

For example, one application might use a property called state. In one case, "state" may refer to a country or region, and in another case it may refer to the state of some document in a process. Both properties are made unambiguous for an item by adding a URI prefix to the property names, as in the following example:

urn:schemas-domain1-tld:state
urn:schemas-domain2-tld:state

The two names are broken down into the parts shown in the following tables.

urn:schemas-domain1-tld:state

URI component	Value
Namespace URI	urn:schemas-domain1-tld:
Property name (local part)	state
Full name	urn:schemas-domain1-tld:state

urn:schemas-domain2-tld:state

URI component	Value
Namespace URI	urn:schemas-domain2-tld:
Property name (local part)	state
Full name	urn:schemas-domain2-tld:state