Oracle RETURNING INTO 用法示例

本文介绍如何在Oracle数据库中使用RETURNINGINTO子句返回由DML语句(如INSERT、UPDATE和DELETE)影响的行的列值。通过示例展示了如何返回单个值及多个值到集合中,并结合了动态SQL的应用。

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;

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
l_id t1.id%TYPE;
BEGIN
INSERT INTO t1 VALUES (t1_seq.nextval, 'FOUR')
RETURNING id INTO l_id;
COMMIT;

DBMS_OUTPUT.put_line('ID=' || l_id);
END;
/
ID=4

PL/SQL procedure successfully completed.

SQL>

The syntax is also available for update and delete statements.

SET SERVEROUTPUT ON
DECLARE
l_id t1.id%TYPE;
BEGIN
UPDATE t1
SET description = description
WHERE description = 'FOUR'
RETURNING id INTO l_id;

DBMS_OUTPUT.put_line('UPDATE ID=' || l_id);

DELETE FROM t1
WHERE description = 'FOUR'
RETURNING id INTO l_id;

DBMS_OUTPUT.put_line('DELETE ID=' || l_id);

COMMIT;
END;
/
UPDATE ID=4
DELETE ID=4

PL/SQL procedure successfully completed.

SQL>

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;
l_tab t_tab;
BEGIN
UPDATE t1
SET description = description
RETURNING id 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

PL/SQL procedure successfully completed.

SQL>

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

PL/SQL procedure successfully completed.

SQL>

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

PL/SQL procedure successfully completed.

SQL>

For more information see:

Hope this helps.

--End--

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