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<p class=MsoNormal><span style='color:#1F497D'>I was thinking something that
limited the total records that were returned; everything outside of the limit
window (start record, num rows) would not be accessible via the api at all.
Additional results would require a second select. This might be a better
fit for the standard select than the scrollable reader?<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>To clarify, in SQL I would do
something like this for the first page of results:<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>SELECT id, name<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>FROM tablename<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>LIMIT 0,20<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>And this for the second page:<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>SELECT id, name<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>FROM tablename<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>LIMIT 20,20<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Etc, etc,<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Because HTTP is stateless, there
is no reason to make rows outside of the selected set available, unless there
is some kind of feature cache at the FDO level that would make subsequent
selects more efficient.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Jason<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Orest
Halustchak<br>
<b>Sent:</b> Monday, October 20, 2008 12:49<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> RE: [fdo-internals] RFC 26 - New Extended Select
commandandScrollable Reader - for review<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Hi Jason,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>So, this limit would
be something that would return an end of fetch after reading
‘limit’ number of records? But, then you can reset it I guess when
you want to get the next page (maybe just by calling ReadAtIndex() again). An
issue with the scrollable reader is that you can read forwards or backwards,
and jump to a new record index at any time. So, I think adding a limit would
complicate this mechanism – knowing when to reset it or what it means
after jumping to a new record.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Thanks,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Orest.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Jason Birch<br>
<b>Sent:</b> Monday, October 20, 2008 3:03 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> RE: [fdo-internals] RFC 26 - New Extended Select command
andScrollable Reader - for review<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>I don’t have any direct
experience with this because MapGuide doesn’t currently doesn’t
allow access to these commands. I certainly see value in making these
part of the common feature set though. Maybe I’ll eventually be
able to do sorting on SDF results via MapGuide </span><span style='font-family:
Wingdings;color:#1F497D'>J</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>One thing that occurred to me
when reading this RFC was that I’d like to see a mechanism to
“page” through results; similar to the LIMIT clause in MySQL.
When displaying result sets in a web environment, you often want to give the
user a small set of the data, and then page through the results N records at a
time. I can currently brute-force this, but it would be more efficient to
handle this on the FDO side, especially for providers where the underlying
storage format has optimized methods of dealing with it. The current
enhancements would make this more efficient to brute-force, but I wonder if
adding parameters to the initial selection (start record, number of results)
would make this even more efficient.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'>Jason<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Orest
Halustchak<br>
<b>Sent:</b> Monday, October 20, 2008 11:24<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> RE: [fdo-internals] RFC 26 - New Extended Select command
andScrollable Reader - for review<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Hi,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>I wonder if anyone
has any comments on this. If nobody has any objections to it, I’d like to
bring it to a vote soon.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Thanks,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Orest.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> fdo-internals-bounces@lists.osgeo.org
[mailto:fdo-internals-bounces@lists.osgeo.org] <b>On Behalf Of </b>Orest
Halustchak<br>
<b>Sent:</b> Friday, October 17, 2008 12:37 PM<br>
<b>To:</b> FDO Internals Mail List<br>
<b>Subject:</b> [fdo-internals] RFC 26 - New Extended Select command and
Scrollable Reader - for review<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Hi,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I’d like to bring your attention to
RFC 26 ( <a href="http://trac.osgeo.org/fdo/wiki/FDORfc26">http://trac.osgeo.org/fdo/wiki/FDORfc26</a>
) which proposes to add a new Extended Select command with uses a Scrollable
feature reader. Basically, this takes what currently are custom commands in the
SDF, SHP, and recently SQLite providers and makes them generic FDO commands.
This will remove special case handling for applications that currently use
these and open the door for generic use by any application.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Please review and provide your feedback.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Thanks,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Orest.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
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