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From Nirmal Fernando <nirmal070...@gmail.com>
Subject Re: [jira] Updated: (DERBY-4623) "XML data type" page in ref needs some modifications
Date Sat, 24 Apr 2010 07:17:07 GMT
Hi John,

2010/4/23 Ян Программист <webautomator@gmail.com>
>>
>>    1) Setting paths of xercesImpl.jar and xalan.jar in the CLASSPATH
>
> No. Xalan library duplicates some code, especially http://xerces.apache.org/xerces2-j/javadocs/api/javax/xml/transform/package-summary.html,
as also as some general stuff required for both Xerces and Xalan. Better idea is to look for http://xml.apache.org/crimson/.
That would minimize count of Java classes loaded at runtime
>>

Xalan is the recommended JAXP parser (I think not a must though) in
http://db.apache.org/derby/docs/10.5/devguide/cdevstandardsxml.html.


>>    2) Command that user should use to start the Derby i.e. java org.apache.derby.tools.ij
>
> Do not understand how it is connected to XML data type

I have attached a patch in
https://issues.apache.org/jira/browse/DERBY-4623, I think you will
understand that after reading the patch.

>>
>>    3) Mention that user needed to create a table which contains XML data type column/s,
because users might thought that they can retrieve XML data from an any table.
>
> Rather an explanation of architecture difference needed for retrieving XML data from
tables without XML type column(s). And do not forget about transactions; and explanation of
a fact that simple locking rows with XML data type records brake data consistency by default
(why consistency couldn't be provided in any way here, actually)
>>

I am not that clear of this, may be you can elaborate more on this. If
you can check with the patch to see, what you want to tell is added on
the patch or not.


>>    4) Mention the requirements that are needed when inserting values to a XML data
typed column, i.e. need of XML keywords document & preserve whitespace, tags etc.
>
> Dealing with whitespace and other stuff is not a problem of SQL parser, it is problem
of client library to prepare XML chunks and insert into SQL in previously prepared places
+ validate (non-text symbols only)

What I wanted to tell here was that you get an error if you do not
include those keywords.

>>
>>    5) A small example which is clearly shows the creation, insertion & selection
using XML data type.
>
> I think I guess where is the problem. Check out the PDF which I attached to this post.
Described features differ in QA & QC conformance levels, while being grouped to same
category of standard. That should be a focus.
>

I will try to read it.

Thanks for taking your time to commenting on this.

--
Best Regards,
Nirmal

C.S.Nirmal J. Fernando
Department of Computer Science & Engineering,
Faculty of Engineering,
University of Moratuwa,
Sri Lanka.

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