Assigning FOREIGN KEY, which method is correct?

Hi guys,

I am real new to SQL and just like to clear up some questions regarding to assigning FOREIGN KEY.

Are there any differences in assigning foreign keys this way:

CREATE TABLE NURSE
(EMP_ID VARCHAR2(8) CONSTRAINT fk_nurse_emp REFERENCES EMPLOYEE(EMP_ID),
WARD_ID VARCHAR2(8) CONSTRAINT fk_nurse_ward REFERENCES WARD(WARD_ID),
CONSTRAINT pk_nurse PRIMARY KEY(EMP_ID, WARD_ID));

and this way:

CREATE TABLE NURSE
(EMP_ID VARCHAR2(8),
WARD_ID VARCHAR2(8),
CONSTRAINT fk_nurse_emp FOREIGN KEY(EMP_ID) REFERENCES EMPLOYEE(EMP_ID),
CONSTRAINT fk_nurse_ward FOREIGN KEY(WARD_ID) REFERENCES WARD(WARD_ID),
CONSTRAINT pk_nurse PRIMARY KEY(EMP_ID, WARD_ID));

What are the differences between them?

Many thanks.No difference - except that you couldn't create a composite foreign key with the first method. They are just alternatives.|||Thank you for clearing this up for me andrewst.

Another question, might not be all that important, but which is the preferred method?

I guess the second method is more preferred, as it clearly identifies the FOREIGN KEYS, but it takes more lines. I just like to learn the basic conventions first and stick to it.|||Well it's really a matter of personal taste and/or company policy. But since the second syntax works for all foreign keys and the first works only for single-column foreign keys, the second syntax could be preferred.