mirror of https://github.com/postgres/postgres
69 lines
1.5 KiB
SQL
69 lines
1.5 KiB
SQL
--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;
|