Re: SETLL in SQL ?

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

David,

Closing the cursor might have a performance impact that you aren't 
expecting.  Though, I have to admit that it's what I usually do, because 
I'm working in an MVC paradigm where I want my business logic to be 
"stateless", so I can't maintain a cursor position between calls.

But, assuming you don't need to be stateless....  If you're trying to 
implement a single-page load subfile with SQL, consider using a 
scrollable cursor, and using the FETCH statement.  Fetch can be coded 
with FIRST, LAST, NEXT or PRIOR to let you fetch the first record in the 
result set, the last record in the result set, the next record, or the 
prior record, respectively.

It's not quite like SETLL -- you can't position to a particular key in 
the result set -- but you don't really need to position by key when 
filling a subfile.  You only need to be able to move forward and 
backward, really.  To scroll forward, you only need to know the page 
size, and run a loop (or fetch into an array) that fetches the next X 
records.  To scroll backward, you need to know how many records you 
loaded onto the current screen, plus the page size, so you can scroll 
backward first by what's on the screen (to position the cursor before 
them) THEN read the previous X number of records into your subfile. 
With a little planning, it's actually very easy.


David Foxwell wrote:
> I'm looking at a progrram that does charges a subfile with SETLL
> followed by READE on ROLLUP, SETGT followed by READPE on ROLLDOWN.
>
> What would be the equivalent in SQL if I wanted to replace the
> SETLL/GT?
>
> Close cursor?