How to use Bulk Collect and Forall

Question

Hi all,
We are on Oracle 10g. I have a requirement to read from table A and then for each record in table A, find matching rows in table B and then write the identified information in table B to the target table (table C). In the past, I had used two ‘cursor for loops’ to achieve that. To make the new procedure, more efficient, I would like to learn to use ‘bulk collect’ and ‘forall’.
Here is what I have so far:
DECLARE
TYPE employee_array IS TABLE OF EMPLOYEES%ROWTYPE;
employee_data  employee_array;
TYPE job_history_array IS TABLE OF JOB_HISTORY%ROWTYPE;
Job_history_data   job_history_array;
BatchSize CONSTANT POSITIVE := 5;
-- Read from File A
CURSOR c_get_employees IS
         SELECT  Employee_id,
                   first_name,
                   last_name,
                   hire_date,
                   job_id
          FROM EMPLOYEES;
-- Read from File B based on employee ID in File A
CURSOR c_get_job_history (p_employee_id number) IS
         select start_date,
                  end_date,
                  job_id,
                  department_id
         FROM JOB_HISTORY
         WHERE employee_id = p_employee_id;
BEGIN
    OPEN c_get_employees;
    LOOP
        FETCH c_get_employees BULK COLLECT INTO employee_data.employee_id.LAST,
                                                                          employee_data.first_name.LAST,
                                                                          employee_data.last_name.LAST,
                                                                          employee_data.hire_date.LAST,
                                                                          employee_data.job_id.LAST
         LIMIT BatchSize;
        FORALL i in 1.. employee_data.COUNT
                Open c_get_job_history (employee_data(i).employee_id);
                FETCH c_get_job_history BULKCOLLECT INTO job_history_array LIMIT BatchSize;
                         FORALL k in 1.. Job_history_data.COUNT LOOP
                                        -- insert into FILE C
                                          INSERT INTO MY_TEST(employee_id, first_name, last_name, hire_date, job_id)
                                                            values (job_history_array(k).employee_id, job_history_array(k).first_name,
                                                                      job_history_array(k).last_name, job_history_array(k).hire_date,
                                                                      job_history_array(k).job_id);
                                         EXIT WHEN job_ history_data.count < BatchSize                        
                         END LOOP;                          
                         CLOSE c_get_job_history;                          
                 EXIT WHEN employee_data.COUNT < BatchSize;
       END LOOP;
        COMMIT;
        CLOSE c_get_employees;
END;
                 When I run this script, I get
[Error] Execution (47: 17): ORA-06550: line 47, column 17:
PLS-00103: Encountered the symbol "OPEN" when expecting one of the following:
   . ( * @ % & - + / at mod remainder rem select update with
   <an exponent (**)> delete insert || execute multiset save
   merge
ORA-06550: line 48, column 17:
PLS-00103: Encountered the symbol "FETCH" when expecting one of the following:
   begin function package pragma procedure subtype type use
   <an identifier> <a double-quoted delimited-identifier> form
   current cursorWhat is the best way to code this? Once, I learn how to do this, I apply the knowledge to the real application in which file A would have around 200 rows and file B would have hundreds of thousands of rows.
Thank you for your guidance,
Seyed

Answer 1

Hello BlueShadow,
Following your advice, I modified a stored procedure that initially was using two cursor for loops to read from tables A and B to write to table C to use instead something like your suggestion listed below:
INSERT INTO tableC
SELECT …
FROM tableA JOIN tableB on (join condition).I tried this change on a procedure writing to tableC with keys disabled. I will try this against the real table that has primary key and indexes and report the result later.
Thank you very much,
Seyed