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--Column ID of table A is primary key:
CREATE TABLE A (
ID int4 not null,
id1 int4 not null,
primary key (ID,ID1)
);
--Columns REFB of table B and REFC of C are foreign keys referenting ID of A:
CREATE TABLE B (
REFB int4,
REFB1 INT4
);
CREATE INDEX BI ON B (REFB);
CREATE TABLE C (
REFC int4,
REFC1 int4
);
CREATE INDEX CI ON C (REFC);
--Trigger for table A:
CREATE TRIGGER AT BEFORE DELETE ON A FOR EACH ROW
EXECUTE PROCEDURE
check_foreign_key (2, 'cascade', 'ID','id1', 'B', 'REFB','REFB1', 'C', 'REFC','REFC1');
CREATE TRIGGER AT1 AFTER UPDATE ON A FOR EACH ROW
EXECUTE PROCEDURE
check_foreign_key (2, 'cascade', 'ID','id1', 'B', 'REFB','REFB1', 'C', 'REFC','REFC1');
CREATE TRIGGER BT BEFORE INSERT OR UPDATE ON B FOR EACH ROW
EXECUTE PROCEDURE
check_primary_key ('REFB','REFB1', 'A', 'ID','ID1');
CREATE TRIGGER CT BEFORE INSERT OR UPDATE ON C FOR EACH ROW
EXECUTE PROCEDURE
check_primary_key ('REFC','REFC1', 'A', 'ID','ID1');
-- Now try
INSERT INTO A VALUES (10,10);
INSERT INTO A VALUES (20,20);
INSERT INTO A VALUES (30,30);
INSERT INTO A VALUES (40,41);
INSERT INTO A VALUES (50,50);
INSERT INTO B VALUES (1); -- invalid reference
INSERT INTO B VALUES (10,10);
INSERT INTO B VALUES (30,30);
INSERT INTO B VALUES (30,30);
INSERT INTO C VALUES (11); -- invalid reference
INSERT INTO C VALUES (20,20);
INSERT INTO C VALUES (20,21);
INSERT INTO C VALUES (30,30);
-- now update work well
update A set ID = 100 , ID1 = 199 where ID=30 ;
SELECT * FROM A;
SELECT * FROM B;
SELECT * FROM C;
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