xml-dev - Re: XML-QL

[Chris von See <cvonsee@onramp.net>]

> Robert Hansen wrote:
>
>As a programmer though, I see a few ways on how it could be implemented...
>1. Matches could be made on the XML as a stream., and return it as such.  So
>you invoke a method on the Query control which asks for a single match.  The
>application would that find the first match and return only that one. From
>there you could recursively ask for the next match.

The SQL cursor mechanism is perfect for this - it  would allow you to
select a solution set of elements from an XML document, and then iterate
through them one at a time.  Having such a mechanism would also allow you
to retrieve a set of elements, do some selective editing (i.e.
INSERT/UPDATE/DELETE WHERE CURRENT OF in cursor parlance) and then put the
elements into a new document.

Having a cursor mechanism would be a huge benefit to XML-QL.

>
>2. Return all of the matches in a single action as a single XML document.
>The problem is that if the XML document is very long, this could take some
>time (even days... if the XML document was big enough).

Cursors could solve this as well, I think.

>Does anyone have any thoughts on this??  I was actually thinking about
>creating a search application based on the current XML-QL note, and have not
>decided on how the interface should work.  For those familiar with
>Microsoft's ADO control, I was thinking something like that.  In which case,

You might be better off creating something akin to Microsoft's ODBC driver
mechanism, where you could not only issue queries against documents but
also retrieve info about the document's metadata (like the SQL_COLUMNS and
SQL_TABLES mechanisms in ODBC).  Also, an ODBC-like mechansim would be much
better suited to use on non-Windows systems.



Chris von See

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