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In computing, a Uniform Resource Name (URN) is the historical name for a Uniform Resource Identifier (URI) that uses the scheme. A URI is a string of characters used to identify a name of a web resource. Such identification enables interaction with representations of the web resource over a network, typically the World Wide Web, using specific protocols. Defined in 1997 in RFC 2141, URNs were intended to serve as persistent, location-independent identifiers, allowing the simple mapping of namespaces into a single URN namespace. The existence of such a URI does not imply availability of the identified resource, but such URIs are required to remain globally unique and persistent, even when the resource ceases to exist or becomes unavailable. Since URNs were originally intended in the 1990s to be part of a three-part information architecture for the Internet, along with URLs and Uniform Resource Characteristics (URCs), a metadata framework. However, URCs never progressed past the conceptual stage, and other technologies such as the Resource Description Framework later took their place. ==Syntax== The syntax of a URN is represented in Backus-Naur form as: : This renders as: : The leading sequence is case-insensitive. is the namespace identifier, which determines the syntactic interpretation of , the namespace-specific string. The functional requirements for Uniform Resource Names are described in 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Uniform Resource Name」の詳細全文を読む スポンサード リンク
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