Re: RPG400-L Digest, Vol 14, Issue 336

Marvin

I thought this was an estimate only for the OPEN - much the same as SQLERRD(3) which is documented like this for the PREPARE -

For the PREPARE statement, contains the estimated number of rows selected. If the number of rows is greater than 2 147 483 647, then 2 147 483 647 is returned.

There've been other threads about this, and I think it has been said the only sure way to get row count is SELECT COUNT(*) FROM TABLE

Now I'm very happy to be mistaken here, because I'd love to have the simple answer from time to time, the SQLERRD(3) answer. Or the GET DIAGNOSTICS answer - oh, that array element IS updated with the number or rows retrieved with FETCH - useful for multiple-row fetches.

I do see that the documentation for DB2_NUMBER_ROWS says it IS the number of rows after an OPEN or FETCH, but with a SENSITIVE cursor it is an estimate. I see that default for SENSITIVE on a cursor is ASENSITIVE, so that what you get depends.

Any takers on whether the GET DIAGNOSTICS value is reliable for managing a loop? Under what conditions?

Regards
Vern

On 9/14/2015 2:43 PM, Marvin Radding wrote:

Mitch,

There is one method that would be a short cut. GET DIAGNOSTICs can provide the total number of records in the data set after the open. That can control the number of records fetched in the FETCH INTO statement.

After the open you can code:

/exec sql
GET DIAGNOSTICS :row_count = DB2_NUMER_ROWS;
/end


Marvin

------------------------------

message: 8
date: Mon, 14 Sep 2015 18:17:00 +0000 (UTC)
from: Mitch Gallman <qtemp@xxxxxxx>
subject: Re: Loading arrayDS from sql select into statement?

I've used the following article several times as a reference: http://www.itjungle.com/fhg/fhg052009-story01.html
I've never had to do a select count prior to doing the fetch.
Mitch


On Monday, September 14, 2015 1:58 PM, "Koester, Michael" <mkoester@xxxxxxxxxxxxx> wrote:


Charles,

Would be nice if you could use SELECT INTO along with FETCH FIRST XX
ROWS...

After getting the count (select count(*) into :resultCount from...), and declaring and opening a cursor, I can successfully use

? ? exec sql
? ? fetch MyCursor for :resultCount rows
? ? ? into :ArrayDS;
? ? ? ? ? ? ? ? ? ? ? ?
But there apparently are no shorter shortcuts.

Michael Koester
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