Create constraint

Posted 21 January 2013 - 06:13 PM

how can use constraint in last line of this code, I has composite primary key their


CREATE TABLE invoption
(
   saleinv          CHAR(6)      CONSTRAINT nn_invoption_saleinv NOT NULL 
                                 CONSTRAINT fk_invoption_saleinv REFERENCES saleinv (saleinv),
   ocode            CHAR(4)      CONSTRAINT nn_invoption_ocode NOT NULL
                                 CONSTRAINT fk_invoption_ocode REFERENCES options (ocode),
   saleprice        NUMBER(7,2)  CONSTRAINT nn_invoption_saleprice NOT NULL,
                                  UNIQUE (saleinv, ocode)
 );