PostgreSQL: NULL value in foreign key column
Solution 1:
Works for me in 9.3 after correcting a missing comma. I'm sure it will work also in 9.1
create table quotations (
receipt_id bigint not null primary key
);
create table order_confirmations (
receipt_id bigint not null primary key,
fk_quotation_receipt_id bigint references quotations (receipt_id)
);
insert into order_confirmations (receipt_id, fk_quotation_receipt_id) values
(1, null);
Confirmation will include:
INSERT 0 1