ORACLE批量绑定FORALL与BULK COLLECT【转】

FORALL与BULK COLLECT的使用方法:
1．使用FORALL比FOR效率高，因为前者只切换一次上下文，而后者将是在循环次数一样多个上下文间切换。

2．使用BLUK COLLECT一次取出一个数据集合，比用游标条取数据效率高，尤其是在网络不大好的情况下。但BLUK COLLECT需要大量内存。

例子:

Sql代码



create table test_forall ( user_id number(10), user_name varchar2(20));

create table test_forall ( user_id number(10), user_name varchar2(20));

select into 中使用bulk collect

Sql代码



DECLARE

TYPE table_forall IS TABLE OF test_forall%ROWTYPE;

v_table table_forall;

BEGIN

SELECT mub.user_id,mub.user_name

BULK COLLECT INTO v_table

FROM mag_user_basic mub

WHERE mub.user_id BETWEEN 10000 AND 10100;

FORALL idx IN 1..v_table.COUNT

INSERT INTO test_forall VALUES v_table(idx);

--VALUES(v_table(idx).user_id,v_table(idx).user_name);Error

--在PL/SQL中，BULK In-BIND与RECORD，%ROWTYPE是不能在一块使用的，

--也就是说，BULK In-BIND只能与简单类型的数组一块使用

COMMIT;

EXCEPTION

WHEN OTHERS THEN

ROLLBACK;

END;

DECLARE
TYPE table_forall IS TABLE OF test_forall%ROWTYPE;
v_table table_forall;
BEGIN
SELECT mub.user_id,mub.user_name
BULK COLLECT INTO v_table
FROM mag_user_basic mub
WHERE mub.user_id BETWEEN 10000 AND 10100;
FORALL idx IN 1..v_table.COUNT
INSERT INTO test_forall VALUES v_table(idx);
--VALUES(v_table(idx).user_id,v_table(idx).user_name);Error
--在PL/SQL中，BULK In-BIND与RECORD，%ROWTYPE是不能在一块使用的，
--也就是说，BULK In-BIND只能与简单类型的数组一块使用
COMMIT;

EXCEPTION
WHEN OTHERS THEN
ROLLBACK;

END;

fetch into 中使用bulk collect

Sql代码



DECLARE

TYPE table_forall IS TABLE OF test_forall%ROWTYPE;

v_table table_forall;

CURSOR c1 IS

SELECT mub.user_id,mub.user_name

FROM mag_user_basic mub

WHERE mub.user_id BETWEEN 10000 AND 10100;

BEGIN

OPEN c1;

--在fetch into中使用bulk collect

FETCH c1 BULK COLLECT INTO v_table;

FORALL idx IN 1..v_table.COUNT

INSERT INTO test_forall VALUES v_table(idx);

COMMIT;

EXCEPTION

WHEN OTHERS THEN

ROLLBACK;

END;

DECLARE
TYPE table_forall IS TABLE OF test_forall%ROWTYPE;
v_table table_forall;

CURSOR c1 IS
SELECT mub.user_id,mub.user_name
FROM mag_user_basic mub
WHERE mub.user_id BETWEEN 10000 AND 10100;
BEGIN
OPEN c1;
--在fetch into中使用bulk collect
FETCH c1 BULK COLLECT INTO v_table;

FORALL idx IN 1..v_table.COUNT
INSERT INTO test_forall VALUES v_table(idx);
COMMIT;

EXCEPTION
WHEN OTHERS THEN
ROLLBACK;
END;

在returning into中使用bulk collect

Sql代码



CREATE TABLE test_forall2 AS SELECT * FROM test_forall;

----在returning into中使用bulk collect

DECLARE

TYPE IdList IS TABLE OF test_forall.User_Id%TYPE;

enums IdList;

TYPE NameList IS TABLE OF test_forall.user_name%TYPE;

names NameList;

BEGIN

DELETE FROM test_forall2 WHERE user_id = 10100

RETURNING user_id, user_name BULK COLLECT INTO enums, names;

dbms_output.put_line('Deleted ' || SQL%ROWCOUNT || ' rows:');

FOR i IN enums.FIRST .. enums.LAST

LOOP

dbms_output.put_line('User #' || enums(i) || ': ' || names(i));

END LOOP;

COMMIT;

EXCEPTION

WHEN OTHERS THEN

ROLLBACK;

END;

CREATE TABLE test_forall2 AS SELECT * FROM test_forall;
----在returning into中使用bulk collect
DECLARE
TYPE IdList IS TABLE OF test_forall.User_Id%TYPE;
enums IdList;
TYPE NameList IS TABLE OF test_forall.user_name%TYPE;
names NameList;
BEGIN
DELETE FROM test_forall2 WHERE user_id = 10100
RETURNING user_id, user_name BULK COLLECT INTO enums, names;
dbms_output.put_line('Deleted ' || SQL%ROWCOUNT || ' rows:');
FOR i IN enums.FIRST .. enums.LAST
LOOP
dbms_output.put_line('User #' || enums(i) || ': ' || names(i));
END LOOP;
COMMIT;

EXCEPTION
WHEN OTHERS THEN
ROLLBACK;

END;

批量更新中，将for改成forall

Sql代码



DECLARE

TYPE NumList IS VARRAY(20) OF NUMBER;

depts NumList := NumList(10, 30, 70, ...);

-- department numbers

BEGIN

...

FOR i IN depts.FIRST..depts.LAST

LOOP

...

--UPDATE statement is sent to the SQL engine

-- with each iteration of the FOR loop!

UPDATE emp SET sal = sal * 1.10 WHERE deptno = depts(i);

END LOOP:

END;

DECLARE
TYPE NumList IS VARRAY(20) OF NUMBER;
depts NumList := NumList(10, 30, 70, ...);
-- department numbers
BEGIN
...
FOR i IN depts.FIRST..depts.LAST
LOOP
...
--UPDATE statement is sent to the SQL engine
-- with each iteration of the FOR loop!
UPDATE emp SET sal = sal * 1.10 WHERE deptno = depts(i);
END LOOP:
END;

Sql代码



--UPDATE statement is sent to the SQL engine just once, with the entire nested table

FORALL i IN depts.FIRST..depts.LAST

UPDATE emp SET sal = sal * 1.10 WHERE deptno = depts(i);

--UPDATE statement is sent to the SQL engine just once, with the entire nested table
FORALL i IN depts.FIRST..depts.LAST
UPDATE emp SET sal = sal * 1.10 WHERE deptno = depts(i);

本文原帖：http://log-cd.javaeye.com/blog/411122