ORACLE RETURNING 语句的使用方法
1.The RETURNING INTO clause allows us to return column values for rows affected by DML statements. The following test table is used to demonstrate this clause.
DROP TABLE t1; DROP SEQUENCE t1_seq; CREATE TABLE t1 ( ID NUMBER(10), DESCRIPTION VARCHAR2(50), CONSTRAINT t1_pk PRIMARY KEY (id)); CREATE SEQUENCE t1_seq; INSERT INTO t1 VALUES (t1_seq.nextval, 'ONE'); INSERT INTO t1 VALUES (t1_seq.nextval, 'TWO'); INSERT INTO t1 VALUES (t1_seq.nextval, 'THREE'); COMMIT;
2.When we insert data using a sequence to generate our primary key value, we can return the primary key value as follows.
SET SERVEROUTPUT ON
DECLARE
v_id t1.id%TYPE;
BEGIN
INSERT INTO t1
VALUES (t1_seq.nextval, 'FOUR')
RETURNING id INTO v_id;
COMMIT;
DBMS_OUTPUT.put_line('ID=' || v_id);
END;
/
ID = 4
3.The syntax is also available for update and delete statements.
SET SERVEROUTPUT ON
DECLARE
v_id t1.id%TYPE;
BEGIN
UPDATE t1
SET description = description
WHERE description = 'FOUR'
RETURNING id INTO v_id;
DBMS_OUTPUT.put_line('UPDATE ID=' || v_id);
DELETE FROM t1
WHERE description = 'FOUR'
RETURNING id INTO v_id;
DBMS_OUTPUT.put_line('DELETE ID=' || v_id);
COMMIT;
END;
/
UPDATE ID = 4
DELETE ID = 4
4.When DML affects multiple rows we can still use the RETURNING INTO, but now we must return the values into a collection using the BULK COLLECT clause.
SET SERVEROUTPUT ON
DECLARE
TYPE t_tab IS TABLE OF t1.id%TYPE;
v_tab t_tab;
BEGIN
UPDATE t1
SET description = description
RETURNING id BULK COLLECT INTO v_tab;
FOR i IN v_tab.first .. l_tab.last LOOP
DBMS_OUTPUT.put_line('UPDATE ID=' || l_tab(i));
END LOOP;
COMMIT;
END;
/
UPDATE ID = 1
UPDATE ID = 2
UPDATE ID = 3
5.We can also use the RETURNING INTO clause in combination with bulk binds.
SET SERVEROUTPUT ON
DECLARE
TYPE t_desc_tab IS TABLE OF t1.description%TYPE;
TYPE t_tab IS TABLE OF t1%ROWTYPE;
l_desc_tab t_desc_tab := t_desc_tab('FIVE', 'SIX', 'SEVEN');
l_tab t_tab;
BEGIN
FORALL i IN l_desc_tab.first .. l_desc_tab.last
INSERT INTO t1
VALUES (t1_seq.nextval, l_desc_tab(i))
RETURNING id, description BULK COLLECT INTO l_tab;
FOR i IN l_tab.first .. l_tab.last LOOP
DBMS_OUTPUT.put_line('INSERT ID=' || l_tab(i).id || ' DESC=' || l_tab(i).description);
END LOOP;
COMMIT;
END;
/
INSERT ID = 5 DESC =FIVE
INSERT ID = 6 DESC =SIX
INSERT ID = 7 DESC =SEVEN
6.This functionality is also available from dymanic SQL.
SET SERVEROUTPUT ON
DECLARE
TYPE t_tab IS TABLE OF t1.id%TYPE;
l_tab t_tab;
BEGIN
EXECUTE IMMEDIATE 'UPDATE t1
SET description = description
RETURNING id INTO :l_tab'
RETURNING BULK COLLECT INTO l_tab;
FOR i IN l_tab.first .. l_tab.last LOOP
DBMS_OUTPUT.put_line('UPDATE ID=' || l_tab(i));
END LOOP;
COMMIT;
END;
/
UPDATE ID = 1
UPDATE ID = 2
UPDATE ID = 3