drop table product_master;

drop table sales_order;

drop table product_order;

CREATE TABLE PRODUCT_MASTER (PRODUCT_NO VARCHAR2(6) PRIMARY KEY);

create table sales_order (order_no varchar2(6) PRIMARY KEY);

create table product_order 
(detlorder_no varchar2(6) NOT NULL, 
product_no    varchar2(6) NOT NULL,
qty_ordered   number(8),
qty_disp      number(8), 
product_rate  number(8,2)); 


alter table product_order add constraint pk_product_order primary key (detlorder_no, product_no);

alter table product_order add constraint fk_so_po foreign key (detlorder_no) references sales_order (order_no);

alter table product_order add constraint fk_pm_po foreign key (product_no) references product_master (product_no);