PL/SQL Join Collection Object problems - object

Question

I am working with an Oracle 11g database, release 11.2.0.3.0 - 64 bit production
I have written the following procedure which uses a cursor to collect batches of benefit_ids (which are simply of type NUMBER) from a table called benefit_info. For each benefit_id within each batch, I need to obtain the associated customers and then perform various calculations etc. So far I have the following:
CREATE OR REPLACE PROCEDURE ben_correct(in_bulk_collect_limit IN PLS_INTEGER DEFAULT 1000)
IS
TYPE ben_identity_rec IS RECORD
(
life_scd_id NUMBER,
benefit_id NUMBER
);
TYPE ben_identity_col IS TABLE OF ben_identity_rec INDEX BY PLS_INTEGER;
life_col ben_identity_col;
ben_id NUMBER;
CURSOR benefit_cur
IS
SELECT benefit_id FROM benefit_info;
TYPE benefit_ids_t IS TABLE OF NUMBER INDEX BY PLS_INTEGER;
benefit_ids benefit_ids_t;
PROCEDURE get_next_set_of_incoming(out_benefit_ids OUT NOCOPY benefit_ids_t)
IS
BEGIN
FETCH benefit_cur
BULK COLLECT INTO out_benefit_ids
LIMIT in_bulk_collect_limit;
END;
BEGIN
OPEN benefit_cur;
LOOP
get_next_set_of_incoming(benefit_ids);
/*
The code below is too slow as each benefit_id is considered
individually. Want to change FOR LOOP into LEFT JOIN of benefit_ids
*/
FOR indx IN 1 .. benefit_ids.count LOOP
ben_id := benefit_ids(indx);
SELECT c.life_scd_id, c.benefit_id
BULK COLLECT INTO life_col
FROM customer c
WHERE c.benefit_id = ben_id;
-- Now do further processing with life_col
END LOOP;
EXIT WHEN benefit_ids.count = 0;
END LOOP;
CLOSE benefit_cur;
END;
/
As indicated in the code above, the FOR indx IN 1 .. LOOP is VERY slow, particularly as there are millions of benefit_ids. However, I am aware I can replace the entire FOR LOOP with something like:
SELECT c.life_scd_id, c.benefit_id
BULK COLLECT INTO life_col
FROM customer c
LEFT JOIN table(benefit_ids) b
WHERE b.benefit_id IS NOT NULL;
However, for that to work I think I need to declare an Object type at the schema level as I think in the SELECT query you can join on pure tables or collections of objects. Therefore, from the procedure I remove
TYPE benefit_ids_t IS TABLE OF NUMBER INDEX BY PLS_INTEGER;
and instead at the schema level I have defined
CREATE OR REPLACE TYPE ben_id FORCE AS object
(
benefit_id number
);
CREATE OR REPLACE TYPE benefit_ids_t FORCE AS TABLE OF ben_id;
My revised code essentially becomes:
CREATE OR REPLACE PROCEDURE ben_correct(in_bulk_collect_limit IN PLS_INTEGER DEFAULT 1000)
IS
sql_str VARCHAR2(1000);
TYPE ben_identity_rec IS RECORD
(
life_scd_id NUMBER,
benefit_id NUMBER
);
TYPE ben_identity_col IS TABLE OF ben_identity_rec INDEX BY PLS_INTEGER;
life_col ben_identity_col;
CURSOR benefit_cur
IS
SELECT benefit_id FROM benefit_info;
--- benefit_ids_t has now been declared at schema level
benefit_ids benefit_ids_t;
PROCEDURE get_next_set_of_incoming(out_benefit_ids OUT NOCOPY benefit_ids_t)
IS
BEGIN
FETCH benefit_cur
BULK COLLECT INTO out_benefit_ids
LIMIT in_bulk_collect_limit;
END;
BEGIN
OPEN benefit_cur;
LOOP
get_next_set_of_incoming(benefit_ids);
sql_str := 'SELECT c.life_scd_id, c.benefit_id
FROM customer c
LEFT JOIN table(benefit_ids) b
WHERE b.benefit_id IS NOT NULL';
EXECUTE IMMEDIATE sql_str BULK COLLECT INTO life_col;
-- Now do further processing with life_col
EXIT WHEN benefit_ids.count = 0;
END LOOP;
CLOSE benefit_cur;
END;
/
However, this generates ORA-24344 and PLS-00386 errors, ie type mismatch found at 'OUT_BENEFIT_IDS' between FETCH cursor and INTO variables.
I sort of understand that it is complaining that benefit_ids_t is now a table of ben_ids, which are in turn objects of type number, which is in't quite the same as a table of numbers.
I've tried various attempts at resolving the issues, but I can't seem to quite get it right. Any help would be gratefully appreciated.
Also, any general comments to improve are welcome.

Answer 1

You don't need your table type to be of an object containing a number field, it can just be a table of numbers:
CREATE OR REPLACE TYPE benefit_ids_t FORCE AS TABLE OF number;
Or you can use a built-in type like sys.odcinumberlist, but having your own type under your control isn't a bad thing.
You don't want to use dynamic SQL though; this:
sql_str := 'SELECT c.life_scd_id, c.benefit_id
FROM customer c
LEFT JOIN table(benefit_ids) b
WHERE b.benefit_id IS NOT NULL';
EXECUTE IMMEDIATE sql_str BULK COLLECT INTO life_col;
won't work because benefit_ids isn't in scope when that dynamic statement is executed. You can just do it statically:
SELECT c.life_scd_id, c.benefit_id
BULK COLLECT INTO life_col
FROM table(benefit_ids) b
JOIN customer c
ON c.benefit_id = b.column_value;
which is closer to what you had in your original code.
Your EXIT is also in the wrong place - it will try to process rows in a loop when it doesn't find any. I wouldn't bother with the separate fetch procedure at all, it's easier to follow with the fetch directly in the loop:
BEGIN
OPEN benefit_cur;
LOOP
FETCH benefit_cur
BULK COLLECT INTO benefit_ids
LIMIT in_bulk_collect_limit;
EXIT WHEN benefit_ids.count = 0;
SELECT c.life_scd_id, c.benefit_id
BULK COLLECT INTO life_col
FROM table(benefit_ids) b
JOIN customer c
ON c.benefit_id = b.column_value;
-- Now do further processing with life_col
END LOOP;
CLOSE benefit_cur;
END;
If you did really want your object type, you could keep that, but you would need to make your cursor return instances of that object, via its default constructor:
CURSOR benefit_cur
IS
SELECT ben_id(benefit_id) FROM benefit_info;
The customer query join would then be:
SELECT c.life_scd_id, c.benefit_id
BULK COLLECT INTO life_col
FROM table(benefit_ids) b
JOIN customer c
ON c.benefit_id = b.benefit_id;
As it's an object type you can refer to it's field name, benefit_id, rather than the generic column_value from the scalar type table.