FK question

Hi,

What is a difference, if any, between:
_________________________________
ALTER TABLE ONLY employee_role
ADD CONSTRAINT fk_survey_id_employee_id FOREIGN KEY (survey_id,
employee_id) REFERENCES employee_survey(survey_id, employee_id) MATCH FULL
ON UPDATE C
ASCADE ON DELETE CASCADE;
__________________________________

AND
___________________________________
ALTER TABLE ONLY employee_role
ADD CONSTRAINT fk_survey_id FOREIGN KEY (survey_id) REFERENCES
employee_survey(survey_id) MATCH FULL ON UPDATE C
ASCADE ON DELETE CASCADE;

ALTER TABLE ONLY employee_role
ADD CONSTRAINT fk_employee_id FOREIGN KEY (employee_id) REFERENCES
employee_survey(employee_id) MATCH FULL ON UPDATE C
ASCADE ON DELETE CASCADE;
_____________________________________

Thank you,

Igor