FORALL
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Note:[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
