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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