Oracle Forall

FORALLNote:[from official document]
Example 12-7DELETE Statement in FOR LOOP Statement

DROP TABLE employees_temp;
CREATE TABLE employees_temp AS SELECT *FROM employees;

DECLARE
TYPE NumList IS VARRAY(20) OF NUMBER;
depts NumList := NumList(10, 30, 70); -- department numbers
BEGIN
FORi IN depts.FIRST..depts.LAST LOOP
DELETE FROM employees_temp
WHERE department_id = depts(i);
ENDLOOP;
END;
/

Example 12-9Time Difference for INSERT Statement in FOR LOOP and FORALL Statements

DROP TABLE parts1;
CREATE TABLE parts1 (
pnum INTEGER,
pname VARCHAR2(15)
);

DROP TABLE parts2;
CREATE TABLE parts2 (
pnum INTEGER,
pname VARCHAR2(15)
);

DECLARE
TYPE NumTab IS TABLE OF parts1.pnum%TYPE INDEX BY PLS_INTEGER;
TYPE NameTab IS TABLE OF parts1.pname%TYPE INDEX BY PLS_INTEGER;
pnums   NumTab;
pnames  NameTab;
iterations  CONSTANT PLS_INTEGER:= 50000;
t1  INTEGER;
t2  INTEGER;
t3  INTEGER;
BEGIN
FORj IN 1..iterations LOOP  -- populatecollections
pnums(j) := j;
pnames(j) := 'Part No. ' || TO_CHAR(j);
ENDLOOP;

t1:= DBMS_UTILITY.get_time;

FORi IN 1..iterations LOOP
INSERT INTO parts1 (pnum, pname)
VALUES (pnums(i), pnames(i));
ENDLOOP;

t2:= DBMS_UTILITY.get_time;

FORALL i IN 1..iterations
INSERT INTO parts2 (pnum, pname)
VALUES (pnums(i), pnames(i));

t3:= DBMS_UTILITY.get_time;

DBMS_OUTPUT.PUT_LINE('Execution Time (secs)');
DBMS_OUTPUT.PUT_LINE('---------------------');
DBMS_OUTPUT.PUT_LINE('FOR LOOP: ' || TO_CHAR((t2 - t1)/100));
DBMS_OUTPUT.PUT_LINE('FORALL:   '|| TO_CHAR((t3 - t2)/100));
COMMIT;
END;
/
Result is similar to:

Execution Time (secs)
---------------------
FOR LOOP: 2.16
FORALL:  .11

PL/SQL procedure successfully completed.

Example 12-10FORALL Statement for Subset of Collection

DROP TABLE employees_temp;
CREATE TABLE employees_temp AS SELECT *FROM employees;

DECLARE
TYPE NumList IS VARRAY(10) OF NUMBER;
depts NumList := NumList(5,10,20,30,50,55,57,60,70,75);
BEGIN
FORALL j IN 4..7
DELETE FROM employees_temp WHERE department_id = depts(j);
END;
/

Example 12-26DELETE with RETURN BULK COLLECT INTO in FORALL Statement

DROP TABLE emp_temp;
CREATE TABLE emp_temp AS
SELECT * FROM employees
ORDER BY employee_id, department_id;

DECLARE
TYPE NumList IS TABLE OF NUMBER;
depts  NumList :=NumList(10,20,30);

TYPE enum_t IS TABLE OF employees.employee_id%TYPE;
e_ids  enum_t;

TYPE dept_t IS TABLE OF employees.department_id%TYPE;
d_ids  dept_t;

BEGIN
FORALL j IN depts.FIRST..depts.LAST
DELETE FROM emp_temp
WHERE department_id = depts(j)
RETURNING employee_id, department_id
BULK COLLECT INTO e_ids, d_ids;

DBMS_OUTPUT.PUT_LINE ('Deleted ' || SQL%ROWCOUNT || ' rows:');

FORi IN e_ids.FIRST .. e_ids.LAST
LOOP
DBMS_OUTPUT.PUT_LINE (
'Employee #' || e_ids(i) || ' from dept #' || d_ids(i)
);
ENDLOOP;
END;
/

Deleted 9 rows:
Employee #200 from dept #10
Employee #201 from dept #20
Employee #202 from dept #20
Employee #114 from dept #30
Employee #115 from dept #30
Employee #116 from dept #30
Employee #117 from dept #30
Employee #118 from dept #30
Employee #119 from dept #30