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From IvanLatysh <i...@yourmail.com>
Subject Re: 7.4 Appendix D: JCR 1.0 XPath (Deprecated)
Date Wed, 18 Jul 2007 14:15:19 GMT
Thomas Mueller wrote:

> I was just not sure what you meant with 'entire industry'. I agree XML
> is important for document processing (however I would have probably
> used JSON). But in my view, most data is still accessed using SQL or
> directly from the file system.
I am not talking about IO or how and where documents are stored, I am talking 
about data interoperability.
Just google 'xml data interoperability' and you will see exactly what it is and 
what has been done about it.

>> B.t.w. I integrated Saxon XQuery 1.0 engine into JCR 1.2.
> How does this work, does it convert XQuery to XPath?
XPath is a subset of XQuery so XQuery can't be converted into XPath.
Integration is straight forward - custom URI resolver and simple SAX 
transformer. It is very inefficient but work out of the box.

>> XPath
> For me, XPath was always quite complicated. I would probably get used
> to it, but I prefer more verbose languages.
I can see, that you come from old school DB background, and I can understand 
you. I can say that XPath are more intuitive than SQL, after a chapter or two 
about XPath.

>> * AQM - design to work with JCR Object model and so has limited 
>> functionality
> What functionality are you missing?
I am missing XPath & XQuery as a part of the spec.
And as I sad before AQM is home-grown and it will take a few years to make it 
work, when XQuery already mature enough, i believe if you have a look at AQM and 
  XQuery specs you will see what exactly AQM missing.

> So in your view, JCR is an XML database? For me, JCR is:
> - File System
> - LDAP
> - Subversion
JCR is a content repository and it can not be an RDBMS because JCR data model 
include 2 major entities: Node and Property that RDBMS could not understand.
Please don't mix persistence layer with JCR.

> So you suggest the Jackrabbit persistence should be an XML database?
> And you would remove support for RDBMS / file system persistence /
> Lucene? 
I can see that you mixing up persistence engine, indexing and JCR all together.

> Wouldn't that be quite a big change and restriction?

Ivan Latysh

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