On 26 okt 2008, at 10.44, Thomas wrote:
Currently I have 3 tables:
Product(id, title, price)
Item(id, product_id, order_id, quantity)
Order(id, amount, paid)
So how do I tell PgSQL that
when I remove a given order, it should remove all associated items
also?
Use a foreign key constraint with the appropriate action:
CREATE TABLE Item (
id SERIAL PRIMARY KEY,
product_id INTEGER NOT NULL REFERENCES Product(id) ON DELETE
RESTRICT ON UPDATE CASCADE,
order_id INTEGER NOT NULL REFERENCES Order(id) ON DELETE CASCADE
ON UPDATE CASCADE,
quantity NUMERIC(5,2) NOT NULL
);
For more info, see the docs: http://www.postgresql.org/docs/8.3/
interactive/ddl-constraints.html#DDL-CONSTRAINTS-FK
Sincerely,
Niklas Johansson
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