问题描述
我有点理解，URN用于为资源提供唯一且与位置无关的名称.但是我看不到它们的用处以及它们的工作原理:
I somewhat understand that URNs are used to provide unique and location independent name for the resource. Yet I fail to see their usefulness and how exactly they work:
a)为了使URN真正唯一，必须有一些中央授权机构(类似于域名授权机构)，我们可以在其中注册URN，并以此方式确保它们是唯一的.既然没有任何此类授权，那么我们如何确保我们的URN是唯一的?如果我们做不到.那么拥有它们有什么意义呢?
a) In order for URN to really be unique, there would have to be some central authority (similar to authority for domain names) where we could register URNs and that way ensure they are unique.Since there isn’t any such authority, how else do we make sure that our URNs are unique? And if we can’t. then what’s the point of having them?
b)另外，我不理解采用 urn:NID:NSS 格式的URN背后的原因.是什么使这种格式比 urn:NID:NID1:NSS 更有效/逻辑的?
b) Also,I don’t understand the reasoning behind URNs having the format urn:NID:NSS. What makes this format more efficient/logical than for example urn:NID:NID1:NSS?
c)最后，URN如何帮助我们在Internet上找到资源?
c) And finally, how can URN help us locate a resource on the internet?
我只是想弄清楚为什么URN使用的格式比其他格式(例如urn:NID:NID1:NSS)精湛"
I’m just trying to make sense of why the format URN uses is "superb" to other formats, such as urn:NID:NID1:NSS
推荐答案
有一个中央机构(称为IANA)进行注册命名空间(NID部分)，每个命名空间均负责确保唯一性.
There is a central authority, called IANA, to register namespaces (the NID part), and each namespace is responsible for ensuring uniqueness.
"urn:NID:NSS"描述指出对NSS的解释取决于该值NID.例如，如果NID为"isbn"，则我们知道将NSS解释为ISBN号，如"urn:isbn:0451450523"中所示.
The "urn:NID:NSS" description states the interpretation of NSS depends on the value of NID. For example, if NID is "isbn", then we know to interpret the NSS as an ISBN number, as in "urn:isbn:0451450523".
NSS部分可以包含冒号，因此"urn:example:other:more"是有效的语法. (事实上，有效的URN 从2013-04-24起.)例如，给定"urn:mpeg:mpeg7:schema:2001"，NSS部分为"mpeg7:schema:2001"，我们根据" mpeg名称空间.
The NSS part can contain colons, so "urn:example:other:more" is valid syntax. (And in-fact is a valid URN as of 2013-04-24.) For example, given "urn:mpeg:mpeg7:schema:2001", the NSS part is "mpeg7:schema:2001" and we interpret that according to the rules for the "mpeg" namespace.
如果需要"urn:NID:NID1:NSS"，它将是多余的(某些名称空间不需要嵌套的NID1)并且是多余的(名称空间的权限已经可以将NSS部分划分出来，例如上面的mpeg示例).
Had "urn:NID:NID1:NSS" been required, it would have been redundant (some namespaces don't need a nested NID1) and superfluous (the authority for a namespace can already divide the NSS part up, as in the above mpeg example).
URN与位置无关，这是 URL .
URNs are not about location, that's a URL.
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