RE: Even more embedded SQL.... Thank you EVERYBODY

-----Original Message-----
From: rpg400-l-bounces+cwilt=meaa.mea.com@xxxxxxxxxxxx 
[mailto:rpg400-l-bounces+cwilt=meaa.mea.com@xxxxxxxxxxxx] On 
Behalf Of Alan Shore
Sent: Thursday, August 03, 2006 12:25 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: Even more embedded SQL.... Thank you EVERYBODY


Booth - you and I must be on the same wavelength, or in 
mutual mind-meld
mode or something.
I want to take time to thank everyone who has replied to my 
question, with
suggestions, ideas, thoughts, other questions and especially examples.

I think I have a handle on everything that I need in relation 
to what is
required for SQL and Dynamic sort building, but what bothers me is the
position to aspect of SQL, where the file data is rebuilt, 
with the first
record being equal to or greater than the value that was 
requested to be
positioned to. The problem of paging up from that point 
(before the first
record) will mean yet another re-creation.
So I was thinking of a couple of things
1/. Load the first 9,999 records into a load all sub-file.
If the user wants to go above that, recreate the data and 
load the next
9,999 records etc. etc.
If the user wants to position to a value AND its within this 9,999 NO
PROBLEM
If its outside the range , recreate the data and load the 
applicable 9,999
records into the sub-file.

"Position to" with a load-all subfile?  How are you going to do that?
Save the subf RRN and key so you can have a particular page put back
out.

Have you thought about the effect that having multiple sortable columns
would have?  If the results are sorted by color, then as a user I'd want
to position to a color.  If the results are sorted by name, then I'd
want to position to by name.

2/. Create a file (via DDS) with all the fields defined
COL1, COL2, COL3, COL4, COL5, COL6, COL7 and an additional 
field which is
in effect equal in size to ALL the fields CONCATENATED. This 
field would
now be the key of the file, and depending upon what sort is 
required, build
this field accordingly
for example
if the sort is COL1, COL2, COL3, COL4, COL5, COL6, COL7, the 
this key field
is created as
COL1 concat COL2 concat COL3 concat COL4 concat COL5 concat 
COL6 concat
COL7
and then use regular RPG to handle the page up, page down, position to
page-at-a-time sub-file
Anybody any thoughts on either of these 2 ideas?

The problem with this idea is that DB I/O is pretty expensive.  You'd
get much better performance writing to a user space instead.

HTH,



Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121