Code / Logic review

Question

Hi All,
Please review the following code and logic used for uploading data by converting comma separated value column to multiple rows.
Tables Used.
create table temp_stg
(id number(16),
equip_name varchar2(200),
pcb1 varchar2(50),
pcb2 varchar2(50));
create table temp_org
(equip_name varchar2(200),
pcb varchar2(50));
insert into temp_stg
values (1, 'Equip1', 'PCB1 & PCB2', 'PCB3 & PCB4');
commit
I want the output of following records inserted into temp_org
Equip_name PCBS
Equip1 PCB1
Equip1 PCB2
Equip1 PCB3
Equip1 PCB4
Following is the PL/SQL code to do the same.
DECLARE
CURSOR cur_stg IS
select equip_name, pcb1 || '&' || pcb2 as pcbs
from temp_stg where id = 1;
rec_stg cur_stg%ROWTYPE;
PROCEDURE process_pcbs
IS
l_pcb_str VARCHAR2(500);
l_single_pcb VARCHAR2(50);
l_cnt PLS_INTEGER := 0;
BEGIN
l_pcb_str := rec_stg.pcbs;
while (length(trim(l_pcb_str)) > 0)
LOOP
IF instr(l_pcb_str,'&',1,1) > 0 THEN
l_single_pcb := substr(l_pcb_str,1,instr(l_pcb_str,'&',1,1));
l_pcb_str := substr(l_pcb_str, instr(l_pcb_str,'&',1,1));
ELSE
l_single_pcb := l_pcb_str;
l_pcb_str := NULL;
END IF;
INSERT INTO temp_org
VALUES (rec_stg.equip_name, l_single_pcb);
END LOOP;
COMMIT;
END process_pcbs;
BEGIN
OPEN cur_stg;
LOOP
FETCH cur_stg INTO rec_stg;
EXIT WHEN cur_stg%NOTFOUND;
IF rec_stg.pcbs IS NOT NULL THEN
process_pcbs;
END IF;
END LOOP;
CLOSE cur_stg;
EXCEPTION
WHEN OTHERS THEN
IF cur_stg%ISOPEN THEN CLOSE cur_stg; END IF;
RAISE;
END;
Thanks
Srini

Answer 1

Hi, Srini,
Srinivas_Reddy wrote:
Hi All,
Please review the following code and logic used for uploading data by converting comma separated value column to multiple rows.Code should always be formatted to show the range and structure of multi-line constructs (such as BEGIN... END or LOOP ... END LOOP),
When posting formatted text on this site, type these 6 characters:
{code}
(all lower-case letters, inside curly brackets) before and after sections of formatted text. Don't expect anyone to read your code if it's not formatted.
SQL was designed for handling sets of data. It's inefficient to run (and often more difficult to code) when you try to solve a problem like this by handling one row at a time. If you're INSERTing rows, try to add all the reos with a single INSERT statment, like the one below.
Thanks for posting the CREATE TABLE and INSERT statements.
You can do what you requested without PL/SQL:
INSERT INTO     temp_org (equip_name, pcb)
WITH    cntr     AS
     SELECT     LEVEL     AS n
     FROM      dual
     CONNECT BY     LEVEL <= 2 + ( SELECT  MAX ( LENGTH           ( pcb1 || pcb2 )
                                                       - LENGTH (REPLACE ( pcb1 || pcb2
                           FROM    temp_stg
SELECT     s.equip_name
,     TRIM ( REGEXP_SUBSTR ( s.pcb1 || '&' || s.pcb2
                           , '[^&]+'
                    , 1
                    , c.n
FROM     temp_stg    s
JOIN     cntr         c     ON     c.n     <= 2 + LENGTH          ( pcb1 || pcb2 )
                                  - LENGTH ( REPLACE ( pcb1 || pcb2
;There are good reasons for wanting to use PL/SQL. If you have one, then you can use an INSERT statement like this inside PL/SQL.
This solution does not assume that temp_stg has only one row.
Under some circumstances, such as if pcb1 or pcb2 is NULL, this may result in NULL pcbs being added to temp_org. If you don't want that, add a WHERE clause to the main query. (If you do, you'll probably find it easier to compute the new pcb in another sub-query, and test to see if that is NULL in the main query.)