DB2 for i SQL使用子值删除由外键联接的2个表中的行

Question

I have a parent and a child table joined by parent_id and I want to delete rows from both tables using a value in the child table

this is what I tried and it is not working

WITH
-- DELETE THE COSTS FIRST AND LET DB2 STORE THE IDs IN AN 'OLD TABLE'
DELETED_CHILD(ID) AS (SELECT PAYABLE_ID FROM OLD TABLE (
DELETE FROM MYLIB.MYCOST
WHERE KEY_VALUE = '1000000'
)
),
-- DELETE THE PAYABLE HEADER USING THE DELETED_LINK IDs
DELETED_PARENT(ID) AS (SELECT PAYABLE_ID FROM OLD TABLE (
DELETE FROM MYLIB.MYPAYABLE
WHERE PAYABLE_ID IN (SELECT DISTINCT ID FROM DELETED_CHILD) 
)
) 
(
-- SELECT IN WITH STATEMENT IS MANDATORY USELESS STATEMENT
SELECT * FROM SYSIBM.SYSDUMMY1
);

The Error I get is

Error code -199, SQL state 42601: [SQL0199] Keyword TABLE not expected. Valid tokens: ) FETCH ORDER UNION EXCEPT.

I want to delete all the children per value and then their parents. Any help is appreciated

Answer 1

Someting like this

DECLARE GLOBAL TEMPORARY TABLE DELETED_CHILD AS ( 
SELECT * FROM MYLIB.MYCOST
WHERE KEY_VALUE = '1000000'  
) WITH DATA WITH REPLACE NOT LOGGED;

DECLARE GLOBAL TEMPORARY TABLE DELETED_PARENT AS ( 
SELECT * FROM MYLIB.MYPAYABLE
WHERE PAYABLE_ID IN (SELECT ID FROM QTEMP.DELETED_CHILD) 
) WITH DATA WITH REPLACE NOT LOGGED;

DELETE FROM MYLIB.MYCOST
WHERE ID IN (SELECT ID FROM QTEMP.DELETED_CHILD);

DELETE FROM MYLIB.MYPAYABLE
WHERE PAYABLE_ID IN (SELECT PAYABLE_ID FROM QTEMP.DELETED_PARENT ) ;

select PAYABLE_ID, 'CHILD' TYPEDELETED FROM QTEMP.DELETED_CHILD 
union all
select PAYABLE_ID, 'PARENT' TYPEDELETED FROM QTEMP.DELETED_PARENT ;

Answer 2

If the Foreign Key relationship has been created with " ON DELETE CASCADE "

   DELETE FROM PARENT
        WHERE PARENT_ID in (
                SELECT CHILD_ID FROM CHILD_TABLE
                 WHERE CHILD_FIELD = 'XXXXX'

---

How to setup the Referential / Foreign Key Constraint :

Refer to: W3Schools Foreign Key Constraint

ALTER TABLE MYLIB.MYCOST
    ADD CONSTRAINT fk_MYCOST
    FOREIGN KEY ( PAYABLE_ID )
    REFERENCES MYLIB.MYPAYABLE( PAYABLE_ID )
    ON DELETE CASCADE
    ON UPDATE RESTRICT 

Referential Constaint Caveats:

• Tables Journaled
• Parent ID must be Unique/Primary Key