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From Brian McCallister <mccallis...@forthillcompany.com>
Subject Re: [JXPath] Plans for JNDI, JMX and Filesystems?
Date Sat, 03 Jan 2004 20:04:17 GMT
You may be right. An important thing to keep in mind in O/R mapping, 
though, is that you very rarely  need to do a join in the query (I have 
yet to have to do one in six+ projects I have worked on using OJB) as 
most joins are mapped as properties (collections) on other objects. 
Hierarchical semantics make a lot of sense when querying into what is, 
to the client, just an object graph.

-Brian


On Jan 3, 2004, at 2:44 PM, Dmitri Plotnikov wrote:

> In my opinion, XPath is much too weak of a query language for 
> relational
> databases. What you want is something like XQuery, which is a superset 
> of
> XPath that includes relational semantics a la SQL.
>
> I wonder if there is an open source project similar to JXPath, but with
> XQuery as the base language.  I looked at the SourceForge project 
> called
> JXQuery.  Very interesting, but it does not appear to have ambitions 
> beyond
> XML applications. Did I misunderstand?
>
> Mapping of XPath semantics to Java objects is a highly contraversial 
> issue -
> when I was building JXPath I had to make many decisions on that front 
> that I
> myself was not very comfortable with.  I can only imagine the 
> magnitude of
> this problem if we try to map XQuery to arbitrary object models.  Can
> anybody see an easy solution there?
>
> - Dmitri
>
>
> ----- Original Message -----
> From: "Brian McCallister" <mccallister@forthillcompany.com>
> To: "Jakarta Commons Users List" <commons-user@jakarta.apache.org>
> Sent: Friday, January 02, 2004 11:15 PM
> Subject: Re: [JXPath] Plans for JNDI, JMX and Filesystems?
>
>
>> I don't know about these, but I am trying to talk any of the JXPathers
>> into helping put together the ability to query persistent object 
>> models
>> via OJB (which will mean building OJB queries from JXPath AST's or
>> something)...
>>
>> -Brian
>>
>> On Jan 2, 2004, at 3:49 PM, Michael Nascimento Santos wrote:
>>
>>> Hey,
>>>
>>> I just would like to know if there are any plans for JXPath to 
>>> provide
>>> special support for navigating JNDI, JMX and filesystems.
>>>
>>> Thanks,
>>> Michael
>>>
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>>
>>
>>
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>
>
>
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