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Re: top-level location-path context dependencies

From: Jason Hunter <jhunter@acm.org>
Date: Sun, 18 Apr 2004 12:20:05 -0700
Message-ID: <4082D4E5.2040405@acm.org>
To: Jim Tivy <jimt@bluestream.com>
Cc: Michael Rys <mrys@microsoft.com>, Howard Katz <howardk@fatdog.com>, www-ql@w3.org

But Jim, I'd like to know exactly how you get your $input or $production 
variables bound in your query.  Let's assume your use case is you want 
to query for all foo elements across all documents in your document 
store.  So how do you set up $input?

There's no mechanism in XQuery to see all the documents, so you can't 
use XQuery to set up the binding.

In a Java interface like XQJ you have no visibility into what's already 
in the XQuery engine, so you can't use Java to set up the binding.

Seems to me you're stalled before you even begin!

-jh-

Jim Tivy wrote:

> Folks
> 
> I think we need use cases to discuss.
> 
> What is your use case?
> 
> Let me imagine a use case...:
> 
> For a use case where you have two collections - "production" and "staged".
> I have an application which I want to run against either production or
> staged.  The application has queries.  I would want to have a variable
> called $input which I use in the queries and which I could set as part of
> the context to production or staged.
> 
> Now if I have two collections in each environment - prodNews and stagedNews
> and prodWhitepaper and stagedWhitepaper, then I might want to have two
> variables $news and $whitepaper which I use in my application and which I
> set in the query context according to whether I am going against the
> production or staged collections.
> 
> In this case having input() is not much use, but having variables is.
> 
> Standardizing on default collections for the purpose of interoperability may
> not be a useful pursuit of a standard.  Having a mechanism that allows a
> query to work off its context is probably a useful pursuit of a standard.
> 
> cheers
> Jim
> 
> 
>>-----Original Message-----
>>From: www-ql-request@w3.org [mailto:www-ql-request@w3.org]On Behalf Of
>>Jason Hunter
>>Sent: Sunday, April 18, 2004 11:20 AM
>>To: Michael Rys
>>Cc: Howard Katz; www-ql@w3.org
>>Subject: Re: top-level location-path context dependencies
>>
>>
>>
>>Michael Rys wrote:
>>
>>
>>>In XQuery, the solution is very simple if you make it explicit:
>>>
>>>Bind a variable to the sequence.
>>
>>The other solution is to bring back input() from the May 2003 draft.
>>That's actually more elegant.
>>
>>-jh-
>>
>>
> 
> 
Received on Sunday, 18 April 2004 15:20:35 GMT

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