Create destinations table
CREATE TABLE destinations
(
destinationI_id int primary key,
country varchar(40),
location varchar(40),
traveller int,
foreign key (traveller) references travellers(traveller_id)
);
How to create a composite key
You will to define the column using this syntax, anything in bold is keyword, the other parts your field names
constraint visit_key primary key (destination, purpose, date_of_visit)
CREATE TABLE visits
(
date_of_visit date,
destination int,
purpose int,
foreign key (destination) references destinations(destination_id),
foreign key (purpose) references purpose(id),
constraint visit_key primary key (destination, purpose, date_of_visit)
);