CREATE TABLE Order_items(

order_item_id number(2) not null,
job_id number(2) not null,
task_id number(2) not null,
quantity number(6) not null,
cost number(6,2) not null,
other_details varchar2(128)
);

ALTER TABLE Order_items ADD CONSTRAINT PRIMARY KEY (order_item_id);
ALTER TABLE Order_items ADD CONSTRAINT FOREIGN KEY (job_id) REFERENCES Jobs(job_id);
ALTER TABLE Order_items ADD CONSTRAINT FOREIGN KEY (task_id) REFERENCES Standard_Tasks(task_id);