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Temporary Tables

This is a discussion on Temporary Tables within the DB2 forums, part of the Database Server Software category; --> Looking for a better way to implement this stored procedure. The issue is that at the end of the ...


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  #1 (permalink)  
Old 02-26-2008, 05:59 PM
Anthony Robinison
 
Posts: n/a
Default Temporary Tables

Looking for a better way to implement this stored procedure. The issue is
that at the end of the procedure, when you try to drop the temp table after
you open the cursor, you get an error stating can't perform that action
because there's a pending operation on the temp table (the cursor reading it
I assume)

And if you close the cursor in order to be able to drop the temp table, you
destroy the result table.

If anyone can think of a better way to implement this procedure without the
need of a temp table, I'd appreciate any ideas.

Thanks in advance!

CREATE PROCEDURE AIM.GetRetrievalImageDetail (IN decAIMRetrievalID
DECIMAL(13,0))
------------------------------------------------------------------------
-- SQL Stored Procedure
-- Original Author Date: April 7, 2004
-- Author: Anthony
-- Returns Image detail information for an individual AIMRetrieval.
--
-- April 14, 2004:
-- Removed STATUS as a field being returned from the AIMRetrievedItem Table
-- Changed AvailableFlag from 'Y' and 'N' to 1 and 2 per Stephanie's code.
--
------------------------------------------------------------------------
LANGUAGE SQL
RESULT SETS 1
P1: BEGIN


DECLARE GLOBAL TEMPORARY TABLE RetrievedItem
(AIMRETRIEVEDITEMID DECIMAL(13,0),
ARCHIVERETRIEVALID DECIMAL(13, 0),
AIMDOCUMENTID VARCHAR(256),
ARCHIVEDOCUMENTID VARCHAR(124),
CAPTUREDATE DATE,
ROUTINGTRANSITNUMBER VARCHAR(9),
MICRACCOUNTNUMBER VARCHAR(24),
POSTINGACCOUNTNUMBER VARCHAR(24),
LOCATION VARCHAR(24),
SERIALNUMBER VARCHAR(20),
AMOUNT DECIMAL(13, 2),
ITEMTYPE VARCHAR(20),
SEQUENCENUMBER VARCHAR(24),
SORRYDOCINDICATOR VARCHAR(20),
APPLICATIONID VARCHAR(20),
CREDITDEBITFLAG VARCHAR(5),
IMAGELENGTH INTEGER,
AVAILABLEFLAG INTEGER
) WITH REPLACE;

BEGIN
DECLARE SELECT_HIGHLEVEL CURSOR WITH RETURN FOR
SELECT
AIM.AIMRETRIEVAL.DESCRIPTION, AIM.AIMRETRIEVAL.AIMRETRIEVALRECEIPT,
AIM.STATUS.STATUS
FROM
AIM.AIMRETRIEVAL,
AIM.STATUS
WHERE
AIM.AIMRETRIEVAL.STATUSID = AIM.STATUS.STATUSID
AND decAIMRetrievalID = AIM.AIMRetrieval.AIMRetrievalID;

DECLARE SELECT_CURSOR CURSOR WITH RETURN FOR
SELECT * FROM SESSION.RetrievedItem;

INSERT INTO SESSION.RetrievedItem
(
AIMRETRIEVEDITEMID ,
ARCHIVERETRIEVALID ,
AIMDOCUMENTID ,
ARCHIVEDOCUMENTID ,
CAPTUREDATE ,
ROUTINGTRANSITNUMBER ,
MICRACCOUNTNUMBER ,
POSTINGACCOUNTNUMBER ,
LOCATION ,
SERIALNUMBER ,
AMOUNT ,
ITEMTYPE ,
SEQUENCENUMBER ,
SORRYDOCINDICATOR ,
APPLICATIONID ,
CREDITDEBITFLAG ,
IMAGELENGTH
)
SELECT

AIM.AIMRETRIEVEDITEM.AIMRETRIEVEDITEMID,
AIM.ARCHIVERETRIEVAL.ARCHIVERETRIEVALID, AIM.AIMRETRIEVEDITEM.AIMDOCUMENTID,
AIM.AIMRETRIEVEDITEM.ARCHIVEDOCUMENTID, AIM.AIMRETRIEVEDITEM.CAPTUREDATE,
AIM.AIMRETRIEVEDITEM.ROUTINGTRANSITNUMBER,
AIM.AIMRETRIEVEDITEM.MICRACCOUNTNUMBER,
AIM.AIMRETRIEVEDITEM.POSTINGACCOUNTNUMBER,
AIM.AIMRETRIEVEDITEM.LOCATION, AIM.AIMRETRIEVEDITEM.SERIALNUMBER,
AIM.AIMRETRIEVEDITEM.AMOUNT, AIM.AIMRETRIEVEDITEM.ITEMTYPE,
AIM.AIMRETRIEVEDITEM.SEQUENCENUMBER, AIM.AIMRETRIEVEDITEM.SORRYDOCINDICATOR,
AIM.AIMRETRIEVEDITEM.APPLICATIONID,
AIM.AIMRETRIEVEDITEM.CREDITDEBITFLAG,
Length(AIM.AIMRETRIEVEDITEM.ImageFront)
FROM
AIM.AIMRETRIEVAL,
AIM.STATUS,
AIM.AIMRETRIEVEDITEM,
AIM.ARCHIVERETRIEVAL,
AIM.ARCHIVETYPE
WHERE
AIM.AIMRETRIEVAL.STATUSID = AIM.STATUS.STATUSID
AND AIM.ARCHIVERETRIEVAL.ARCHIVERETRIEVALID =
AIM.AIMRETRIEVEDITEM.ARCHIVERETRIEVALID
AND AIM.AIMRETRIEVAL.AIMRETRIEVALID = AIM.ARCHIVERETRIEVAL.AIMRETRIEVALID
AND AIM.ARCHIVERETRIEVAL.ARCHIVEID = AIM.ARCHIVETYPE.ARCHIVEID
AND AIM.ARCHIVETYPE.ARCHIVETYPE = 'D'
AND AIM.AIMRETRIEVAL.AIMRETRIEVALID = decAIMRetrievalID;

UPDATE SESSION.RetrievedItem SET AVAILABLEFLAG = 2 WHERE
SESSION.RetrievedItem.ImageLength IS NULL OR
SESSION.RetrievedItem.ImageLength = 0;
UPDATE SESSION.RetrievedItem SET AVAILABLEFLAG = 1 WHERE
SESSION.RetrievedItem.ImageLength IS NOT NULL OR
SESSION.RetrievedItem.ImageLength > 0;

OPEN SELECT_HIGHLEVEL;
OPEN SELECT_CURSOR;
--CLOSE SELECT_CURSOR;
--DROP TABLE SESSION.RetrievedItem;
--CLOSE SELECT_HIGHLEVEL;
--CLOSE SELECT_CURSOR;
--BEGIN
--DROP TABLE SESSION.RetrievedItem;
--END;
END;
END P1
__________________
Anthony Robinson


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  #2 (permalink)  
Old 02-26-2008, 05:59 PM
Knut Stolze
 
Posts: n/a
Default Re: Temporary Tables

Anthony Robinison wrote:

> Looking for a better way to implement this stored procedure. The issue is
> that at the end of the procedure, when you try to drop the temp table
> after you open the cursor, you get an error stating can't perform that
> action because there's a pending operation on the temp table (the cursor
> reading it I assume)
>
> And if you close the cursor in order to be able to drop the temp table,
> you destroy the result table.
>
> If anyone can think of a better way to implement this procedure without
> the need of a temp table, I'd appreciate any ideas.
>
> Thanks in advance!
>
> CREATE PROCEDURE AIM.GetRetrievalImageDetail (IN decAIMRetrievalID
> DECIMAL(13,0))
> ------------------------------------------------------------------------
> -- SQL Stored Procedure
> -- Original Author Date: April 7, 2004
> -- Author: Anthony
> -- Returns Image detail information for an individual AIMRetrieval.
> --
> -- April 14, 2004:
> -- Removed STATUS as a field being returned from the AIMRetrievedItem
> Table -- Changed AvailableFlag from 'Y' and 'N' to 1 and 2 per Stephanie's
> code. --
> ------------------------------------------------------------------------
> LANGUAGE SQL
> RESULT SETS 1
> P1: BEGIN
>
>
> DECLARE GLOBAL TEMPORARY TABLE RetrievedItem
> (AIMRETRIEVEDITEMID DECIMAL(13,0),
> ARCHIVERETRIEVALID DECIMAL(13, 0),
> AIMDOCUMENTID VARCHAR(256),
> ARCHIVEDOCUMENTID VARCHAR(124),
> CAPTUREDATE DATE,
> ROUTINGTRANSITNUMBER VARCHAR(9),
> MICRACCOUNTNUMBER VARCHAR(24),
> POSTINGACCOUNTNUMBER VARCHAR(24),
> LOCATION VARCHAR(24),
> SERIALNUMBER VARCHAR(20),
> AMOUNT DECIMAL(13, 2),
> ITEMTYPE VARCHAR(20),
> SEQUENCENUMBER VARCHAR(24),
> SORRYDOCINDICATOR VARCHAR(20),
> APPLICATIONID VARCHAR(20),
> CREDITDEBITFLAG VARCHAR(5),
> IMAGELENGTH INTEGER,
> AVAILABLEFLAG INTEGER
> ) WITH REPLACE;
>
> BEGIN
> DECLARE SELECT_HIGHLEVEL CURSOR WITH RETURN FOR
> SELECT
> AIM.AIMRETRIEVAL.DESCRIPTION, AIM.AIMRETRIEVAL.AIMRETRIEVALRECEIPT,
> AIM.STATUS.STATUS
> FROM
> AIM.AIMRETRIEVAL,
> AIM.STATUS
> WHERE
> AIM.AIMRETRIEVAL.STATUSID = AIM.STATUS.STATUSID
> AND decAIMRetrievalID = AIM.AIMRetrieval.AIMRetrievalID;
>
> DECLARE SELECT_CURSOR CURSOR WITH RETURN FOR
> SELECT * FROM SESSION.RetrievedItem;
>
> INSERT INTO SESSION.RetrievedItem
> (
> AIMRETRIEVEDITEMID ,
> ARCHIVERETRIEVALID ,
> AIMDOCUMENTID ,
> ARCHIVEDOCUMENTID ,
> CAPTUREDATE ,
> ROUTINGTRANSITNUMBER ,
> MICRACCOUNTNUMBER ,
> POSTINGACCOUNTNUMBER ,
> LOCATION ,
> SERIALNUMBER ,
> AMOUNT ,
> ITEMTYPE ,
> SEQUENCENUMBER ,
> SORRYDOCINDICATOR ,
> APPLICATIONID ,
> CREDITDEBITFLAG ,
> IMAGELENGTH
> )
> SELECT
>
> AIM.AIMRETRIEVEDITEM.AIMRETRIEVEDITEMID,
> AIM.ARCHIVERETRIEVAL.ARCHIVERETRIEVALID,
> AIM.AIMRETRIEVEDITEM.AIMDOCUMENTID,
> AIM.AIMRETRIEVEDITEM.ARCHIVEDOCUMENTID, AIM.AIMRETRIEVEDITEM.CAPTUREDATE,
> AIM.AIMRETRIEVEDITEM.ROUTINGTRANSITNUMBER,
> AIM.AIMRETRIEVEDITEM.MICRACCOUNTNUMBER,
> AIM.AIMRETRIEVEDITEM.POSTINGACCOUNTNUMBER, AIM.AIMRETRIEVEDITEM.LOCATION,
> AIM.AIMRETRIEVEDITEM.SERIALNUMBER, AIM.AIMRETRIEVEDITEM.AMOUNT,
> AIM.AIMRETRIEVEDITEM.ITEMTYPE, AIM.AIMRETRIEVEDITEM.SEQUENCENUMBER,
> AIM.AIMRETRIEVEDITEM.SORRYDOCINDICATOR,
> AIM.AIMRETRIEVEDITEM.APPLICATIONID, AIM.AIMRETRIEVEDITEM.CREDITDEBITFLAG,
> Length(AIM.AIMRETRIEVEDITEM.ImageFront)
> FROM
> AIM.AIMRETRIEVAL,
> AIM.STATUS,
> AIM.AIMRETRIEVEDITEM,
> AIM.ARCHIVERETRIEVAL,
> AIM.ARCHIVETYPE
> WHERE
> AIM.AIMRETRIEVAL.STATUSID = AIM.STATUS.STATUSID
> AND AIM.ARCHIVERETRIEVAL.ARCHIVERETRIEVALID =
> AIM.AIMRETRIEVEDITEM.ARCHIVERETRIEVALID
> AND AIM.AIMRETRIEVAL.AIMRETRIEVALID = AIM.ARCHIVERETRIEVAL.AIMRETRIEVALID
> AND AIM.ARCHIVERETRIEVAL.ARCHIVEID = AIM.ARCHIVETYPE.ARCHIVEID
> AND AIM.ARCHIVETYPE.ARCHIVETYPE = 'D'
> AND AIM.AIMRETRIEVAL.AIMRETRIEVALID = decAIMRetrievalID;
>
> UPDATE SESSION.RetrievedItem SET AVAILABLEFLAG = 2 WHERE
> SESSION.RetrievedItem.ImageLength IS NULL OR
> SESSION.RetrievedItem.ImageLength = 0;
> UPDATE SESSION.RetrievedItem SET AVAILABLEFLAG = 1 WHERE
> SESSION.RetrievedItem.ImageLength IS NOT NULL OR
> SESSION.RetrievedItem.ImageLength > 0;


That doesn't make a lot of sense to me. Assuming that ImageLength is 0, you
will set the AVAILABLEFLAG to 2 in the first query (= 0) and change it
right away to 1 in the second query (IS NOT NULL). Did you meant to
use ... AND ... in the 2nd query?

> OPEN SELECT_HIGHLEVEL;
> OPEN SELECT_CURSOR;
> --CLOSE SELECT_CURSOR;
> --DROP TABLE SESSION.RetrievedItem;
> --CLOSE SELECT_HIGHLEVEL;
> --CLOSE SELECT_CURSOR;
> --BEGIN
> --DROP TABLE SESSION.RetrievedItem;
> --END;
> END;
> END P1


If I got this right, then the main logic of your procedure is this:

(1) declare temp table
(2) copy data from 5-way join to temp table
(3) change some data in the temp table
(4) open 1 cursor (SELECT_HIGHLEVEL) that queries the static tables
(5) open 1 cursor (SELECT_CURSOR) that queries the temp table

First, we can ignore step (4) because the temp table isn't needed there.

Next, you can combine (2), (3), and (5) into a single operation and, thus,
avoiding the temp table completely. This would be something like that:

DECLARE select_cursor CURSOR WITH RETURN FOR
SELECT AIM.AIMRETRIEVEDITEM.AIMRETRIEVEDITEMID,
AIM.ARCHIVERETRIEVAL.ARCHIVERETRIEVALID,
AIM.AIMRETRIEVEDITEM.AIMDOCUMENTID,
AIM.AIMRETRIEVEDITEM.ARCHIVEDOCUMENTID,
AIM.AIMRETRIEVEDITEM.CAPTUREDATE,
AIM.AIMRETRIEVEDITEM.ROUTINGTRANSITNUMBER,
AIM.AIMRETRIEVEDITEM.MICRACCOUNTNUMBER,
AIM.AIMRETRIEVEDITEM.POSTINGACCOUNTNUMBER,
AIM.AIMRETRIEVEDITEM.LOCATION,
AIM.AIMRETRIEVEDITEM.SERIALNUMBER,
AIM.AIMRETRIEVEDITEM.AMOUNT,
AIM.AIMRETRIEVEDITEM.ITEMTYPE,
AIM.AIMRETRIEVEDITEM.SEQUENCENUMBER,
AIM.AIMRETRIEVEDITEM.SORRYDOCINDICATOR,
AIM.AIMRETRIEVEDITEM.APPLICATIONID,
AIM.AIMRETRIEVEDITEM.CREDITDEBITFLAG,
Length(AIM.AIMRETRIEVEDITEM.ImageFront),
-- generate the "AVAILABLE_FLAG" on the fly
CASE
WHEN COALESCE(Length(AIM.AIMRETRIEVEDITEM.ImageFront), 0) = 0
THEN 2
ELSE 1
END
FROM AIM.AIMRETRIEVAL,
AIM.STATUS,
AIM.AIMRETRIEVEDITEM,
AIM.ARCHIVERETRIEVAL,
AIM.ARCHIVETYPE
WHERE AIM.AIMRETRIEVAL.STATUSID = AIM.STATUS.STATUSID AND
AIM.ARCHIVERETRIEVAL.ARCHIVERETRIEVALID =
AIM.AIMRETRIEVEDITEM.ARCHIVERETRIEVALID AND
AIM.AIMRETRIEVAL.AIMRETRIEVALID =
AIM.ARCHIVERETRIEVAL.AIMRETRIEVALID AND
AIM.ARCHIVERETRIEVAL.ARCHIVEID = AIM.ARCHIVETYPE.ARCHIVEID AND
AIM.ARCHIVETYPE.ARCHIVETYPE = 'D' AND
AIM.AIMRETRIEVAL.AIMRETRIEVALID = decAIMRetrievalID;

In the above query, I packed the calculation of the AVAILABLE_FLAG in a CASE
expression. That way, you could save at least the 2nd UPDATE operation,
but here we don't need any UPDATE at all.

The COALESCE function returns the first argument that is not NULL. So if
LENGTH(...) returns NULL, then the '0' is used and the AVAILABLE_FLAG is
set to 2. If LENGTH is already 0, then the flag is also set to 2. That
covers both conditions from the 1st update. Consequentially, the ELSE
branch (setting the flag to 1) is only taken if LENGTH is not NULL and if
it is larger than 0. (I assume that my comment on the 2 UPDATE statements
above regarding the conditions was correct...)

--
Knut Stolze
Information Integration
IBM Germany / University of Jena
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