Scott M. wrote:
> No problem CT - - You are not alone when it comes to getting over the
> confusion of using URL's as namespace names. My company is an IT training
> company and whenever I am teaching XML, this issue winds up being the single
> biggest source of confusion. But, once you get your head around the idea,
> other things become much clearer.
>
> Good luck!
>
> -Scott
>
>
> "cj" <cj@nospam.nospam> wrote in message
> news:OBkDFLFWIHA.748@TK2MSFTNGP04.phx.gbl...
>> Thanks very much Scott. That's the kind of explanation I wish I had on so
>> many things. Honestly I think if the standard for web service namespaces
>> was ACME/employees/HR instead of http://www.ACME.com/employees/HR it
>> would have made more sense to me as it doesn't carry the connotation that
>> it's a web address. I would have understood it much quicker and I'm
>> probably not the only person who finds it confusing. But that's ok. Now
>> that I understand it's fine.
>>
>> BTW, I went to a Microsoft Seminar and the speaker said he wasn't going to
>> talk about AJAX since unless we had been living under a rock for the past
>> 3 years we already knew about that. Hey I use AJAX all the time on my
>> kitchen counters! Of course with my great understanding of the lingo the
>> seminar went quite well. ;)
>>
>> Well I've got to go put some things in order now. Oh, sorry, I mean I've
>> go to marshal some things now.
>>
>> Thanks again,
>> CJ
>>
>>
>> Scott M. wrote:
>>> "cj" <cj@nospam.nospam> wrote in message
>>> news:eaqL%23H7VIHA.4440@TK2MSFTNGP06.phx.gbl...
>>>> Yes, that helps. Making a namespace look like a web address is just
>>>> asking for confusion IMHO but that's life.
>>> What you need to understand is that using what looks like a URL for a
>>> namespace name is not directly related to .NET at all and is also not
>>> done just for web service use.
>>>
>>> It is an XML standard per the World Wide Web Consortium (the W3C). The
>>> reason for needing namespaces in XML is because the very nature of XML
>>> allows you to make up tag and attribute names yourself based on the data
>>> you will be passing. If 2 departments within a single company were to be
>>> using XML to represent employee data (for just their department), they
>>> each might inadvertently use the same tag names and/or attribute names.
>>> Now, if those two lists of XML were to get mixed up, it would be very
>>> hard to separate who's data is who's - - namespaces are needed to prevent
>>> this from occuring (because although the tag names might be the same, the
>>> xmlns="" value would be different).
>>>
>>> Now, you may ask "Ok, that makes sense, buy why use URL's and not some
>>> other identifier?". Well, what if the two departments were "Human
>>> Resources" and "Accounts Payable", couldn't they just use "HR" and "AP"
>>> as the namespace names? Perhaps, but what happens if this company were
>>> to merge with another company who is also using XML for just the same
>>> purpose and that company is most likely going to have Human Resources and
>>> Accounts Payable departments as well. If the two companies had been
>>> using "HR" and "AP" as their namespace qualifiers, there would be no way
>>> to tell who's data was who's.
>>>
>>> This is why namespaces are generally specified using URL's, because each
>>> company/organization on the planet is guaranteed to have a unique URL and
>>> so in the first senario above, the namespaces could be:
>>>
>>> http://www.ACME.com/employees/HR
>>> http://www.ACME.com/employees/AP
>>>
>>> And, those namespaces would keep, not only those two departments XML data
>>> separate, but when the new company gets merged with ACME, we still can
>>> keep it all straight because the new company's namespaces would look like
>>> this:
>>>
>>> http://www.OtherCompany.com/employees/HR
>>> http://www.OtherCompany.com/employees/AP
>>>
>>>> So what I'm still wondering is why would it matter if you and I both use
>>>> the same namespace--or would it? It's not actually telling the client
>>>> where to send the request is it?
>>> No. Again, namespaces are not actually resolved by any software, they
>>> just serve as names to group related XML data. As in my example above,
>>> it could be very confusing if your data and my data got mixed up.
>>> Namespaces are not required in all uses of XML because sometimes making
>>> "groups" of XML isn't really necessary, but with web services, they are
>>> because there are many services out there and different services can
>>> still result in similar XML, so we need to keep each service's XML
>>> separate from another's.
>>>
>>>> Does the client know the namespace before it calls the service?
>>> Yes. The proxy classes that are built by Visual Studio (usually hidden
>>> files in the Solution Explorer) will have knowledge of the service
>>> namespace.
>>>
>>>> Perhaps it does and then it waits for a response to come that says it's
>>>> from that web service.
>>> No. Again, namespaces are just strings that identify a group of XML.
>>> They aren't used in web services in this way.
>>>
>>>> In which case it wouldn't matter if both of us used the same namespace
>>>> as long as a client wasn't requesting data from both of us in which case
>>>> it would get confused on responses.
>>> True, but your missing the bigger point. Although it *may* not cause a
>>> problem if two entities use the same namespace, the fact is that it
>>> *could* and to eliminate the possibility, we make sure that different
>>> services use different namespaces. It's more of a programming standard
>>> than a programming issue.
>>>
>>> -Scott
>>>
>>>> Scott M. wrote:
>>>>> A "namespace" looks like a URL, but it is not. In this case "tempuri"
>>>>> stands for "temporary URI", meaning that it is dummy data that you are
>>>>> supposed to change.
>>>>>
>>>>> Namespaces are used in XML (which is the format that your web service
>>>>> sends/receives data) to organize/group XML tags and attributes. This
>>>>> is conceptually the same as how namespaces are used in .NET - - to
>>>>> organize/group classes. The difference being that in .NET, the syntax
>>>>> uses dot notation (i.e. System.Web.UI) and in XML, namespaces use URI
>>>>> (uniform resource indicators), such as "http://www.something.com".
>>>>> Although they look like URL's, they are not and they are not meant to