Foreign keys
Multi-column foreign keys
The references syntax only works for a single-column FK/PK.
There is a more general syntax for use with a multi-column FK/PK.
create table P(
p1_id int not null,
p2_id int not null,
x int,
primary key(p1_id, p2_id)
);
create table F(
f_id int not null primary key,
p1_id int,
p2_id int,
y int,
foreign key(p1_d, p2_id) references P
);
- primary key(p1_id, p2_id): A 2-column PK.
- foreign key(p1_d, p2_id) references P: A 2-column FK that refers to it.
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