Improve company productivity with a Business Account.Sign Up

x
?
Solved

DB2 With statement

Posted on 2010-11-23
4
Medium Priority
?
1,735 Views
Last Modified: 2012-05-10
I want to remove the session temporay table and make it call based so I can quarantee no clashes in concurrent calls to the SP. Can anyone advise how a I change the seesion table to one using the with statement? I would like ot be able to reference the table from theclient code ( as a returned cursor I guess).
0
Comment
Question by:10Pints
  • 2
4 Comments
 

Author Comment

by:10Pints
ID: 34195891
Ooops! sorry for got the code snippet ...
DROP PROCEDURE GetNVPairs <<
CREATE PROCEDURE GetNVPairs(str CLOB(64K)) 
  LANGUAGE SQL
  RESULT SETS 1

 P1:BEGIN
    DECLARE X integer;
    DECLARE SQLSTATE CHAR(5) DEFAULT '00000';
    DECLARE v_a VARCHAR(250);
    DECLARE v_b VARCHAR(250);

    DECLARE GLOBAL TEMPORARY TABLE SESSION.ITEMS
    (
       ordinal integer,
       name   VarChar(50),
       val    VarChar(50)
    )
    WITH REPLACE 
    ON COMMIT
    PRESERVE ROWS
    NOT LOGGED;
  
  BEGIN
    DECLARE iordinal integer;
    DECLARE ia integer;
    DECLARE ib integer;
    DECLARE ic integer;
    DECLARE cur CURSOR FOR SELECT * FROM TABLE(elemIdx( str)) ORDER BY ordinal;
 
    DECLARE cur2 CURSOR  WITH RETURN TO CALLER FOR SELECT * FROM SESSION.ITEMS;
    DELETE FROM SESSION.ITEMS;

    OPEN cur;
    FETCH FROM cur INTO iordinal, ia, ib, ic;

    WHILE(SQLSTATE = '00000') DO
         IF ((ia <> 0) AND ( ib <> 0) AND ( ic <> 0)) then
    	     INSERT INTO SESSION.items(ordinal, name, val) VALUES(iordinal,  SUBSTR( str, ia, ib-ia), SUBSTR( str, ib+1, ic-ib-1));
         END IF;

         FETCH FROM cur INTO iordinal, ia, ib, ic;
    END WHILE;

    CLOSE cur;

    OPEN cur2;

END;
END P1<<

Open in new window

0
 
LVL 37

Accepted Solution

by:
momi_sabag earned 1000 total points
ID: 34195921
you can use the temporary table since every session gets its own copy, so you won't have colisions, but you can also use

with a as (
SELECT * FROM TABLE(elemIdx( str))
)
select iordinal,  SUBSTR( str, ia, ib-ia), SUBSTR( str, ib+1, ic-ib-1)
from a
order by ordinal
0
 
LVL 46

Assisted Solution

by:Kent Olsen
Kent Olsen earned 1000 total points
ID: 34196184
Hi 10pints,

The two techniques have their own usage.

The common table expression that Momi shows is often used when a query needs to process the same set of data more than once or when recursion is needed.  It can also make a query a lot easier to write and understand.

The temporary table that you show is often used to simplify a complex query, when multiple queries need to process the same data, or when one job step (i.e. the stored procedure) needs to hand results to another step in a job.

Unless there are performs reasons to do otherwise, I'll choose the CTE whenever possible.


Good Luck,
Kent
0
 

Author Closing Comment

by:10Pints
ID: 34211619
thanks guys - BRILLIANT!  this cuts my code in less than half and will avid any potential temporary table clashes as the server is multithreaded.
0

Featured Post

Upgrade your Question Security!

Your question, your audience. Choose who sees your identity—and your question—with question security.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

November 2009 Recently, a question came up in the DB2 forum regarding the date format in DB2 UDB for AS/400.  Apparently in UDB LUW (Linux/Unix/Windows), the date format is a system-wide setting, and is not controlled at the session level.  I'm n…
Recursive SQL in UDB/LUW (you can use 'recursive' and 'SQL' in the same sentence) A growing number of database queries lend themselves to recursive solutions.  It's not always easy to spot when recursion is called for, especially for people una…
In response to a need for security and privacy, and to continue fostering an environment members can turn to for support, solutions, and education, Experts Exchange has created anonymous question capabilities. This new feature is available to our Pr…
If you are looking for an automated tool which can generate reports for Outlook emails and other items from PST file, then you can go for Kernel PST Reporter tool. The reports which are created by this tool are helpful to analyze and understand PST …

607 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question