Help with mysql create statement!!!

[j-dearden]

Hey there could some one please explain what this means.

create table order_items
(
order_id int unsigned not null references orders(order_id)
)

i undersant everything except the "references orders(order_id)

i know that orders is the orders table but what exactly is it doing?

cheers

[Roger_Ramjet]

It is creating a Foreign Key constraint on that column - ie. the values entered in this column must already exist in the orders table.
Note that this only applies with the InnoDB table type, it is ignored for all other table types.