INSERT using LOOP with SELECT - oracle

Question

I am trying to insert the data from other table using INSERT/SELECT combo. I also need to insert increment with specific calculation. However, I can't figure out why it is not working.
I have the table (temp_business_area) like this:
----------
| bname |
----------
| London |
| Sydney |
| Kiev |
----------
I would like to have this in enum table:
-----------------------------------------------------------------
| identifier | language_id | code | data | company_limit |
----------------------------------------------------------------|
| BUSINESS_UNIT | 0 | 100 | London | 126 |
| BUSINESS_UNIT | 0 | 200 | Sydney | 126 |
| BUSINESS_UNIT | 0 | 300 | Kiev | 126 |
-----------------------------------------------------------------
But what I get is this:
-----------------------------------------------------------------
| identifier | language_id | code | data | company_limit |
----------------------------------------------------------------|
| BUSINESS_UNIT | 0 | 100 | London | 126 |
| BUSINESS_UNIT | 0 | 100 | Sydney | 126 |
| BUSINESS_UNIT | 0 | 100 | Kiev | 126 |
| BUSINESS_UNIT | 0 | 200 | London | 126 |
| BUSINESS_UNIT | 0 | 200 | Sydney | 126 |
| BUSINESS_UNIT | 0 | 200 | Kiev | 126 |
| BUSINESS_UNIT | 0 | 300 | London | 126 |
| BUSINESS_UNIT | 0 | 300 | Sydney | 126 |
| BUSINESS_UNIT | 0 | 300 | Kiev | 126 |
-----------------------------------------------------------------
And here is my loop.
BEGIN
FOR x IN 1 .. 3 LOOP
INSERT INTO enum (identifier, language_id, code, data, company_limit)
SELECT 'BUSINESS_UNIT', 0, x*100, bname, 126 FROM temp_business_area;
END LOOP;
END;
I can't figure out where am I making mistake. Help?

Answer 1

You are doing three inserts for each row in temp_business_area, that's why you wind up with 9 rows.
From your description of what you want to achieve you don't need the loop at all.
Just use a single insert:
INSERT INTO enum (identifier, language_id, code, data, company_limit)
SELECT 'BUSINESS_UNIT',
0,
row_number() over (order by null) * 100,
bname, 126
FROM temp_business_area;
The SELECT statement will return 3 rows, and each row will be inserted into the enum table. The row_number() function will return an incrementing value for each row (1,2,3) which multplied by 100 will yield the code that you want.
Edit
(after David's comments):
The use of the windowing function does add a bit of an overhead to the statement. If the additional control over the numbering is not needed, using ROWNUM instead will be a bit more efficient (although it won't matter for only three rows).
INSERT INTO enum (identifier, language_id, code, data, company_limit)
SELECT 'BUSINESS_UNIT',
0,
rownum * 100,
bname, 126
FROM temp_business_area;

Answer 2

you may to use two variants else:
declare
i integer := 1;
BEGIN
FOR x IN (select distinct bname from temp_business_area) LOOP
INSERT INTO enum (identifier, language_id, code, data, company_limit)
SELECT 'BUSINESS_UNIT', 0, i*100, x.bname, 126 FROM temp_business_area;
i := i + 1;
END LOOP;
END;
variant 2
BEGIN
FOR x IN 1..3 LOOP
INSERT INTO enum (identifier, language_id, code, data, company_limit)
SELECT distinct 'BUSINESS_UNIT', 0, x*100, bname, 126 FROM temp_business_area WHERE rownum = x;
END LOOP;
END;