CREATE TABLE parent (id integer PRIMARY KEY);
CREATE TABLE child (id integer REFERENCES parent ON DELETE CASCADE);
CREATE FUNCTION silly() RETURNS trigger LANGUAGE plpgsql AS 'BEGIN RETURN NULL; END;';
CREATE TRIGGER silly BEFORE DELETE ON child FOR EACH ROW EXECUTE FUNCTION silly();
INSERT INTO parent VALUES (1);
INSERT INTO child VALUES (1);
DELETE FROM parent WHERE id = 1;
TABLE child;
id
════
1
(1 row)
The trigger function cancels the cascaded delete on "child", and we are left with
a row in "child" that references no row in "parent".
Yours,
Laurenz Albe
