在这个表
CREATE TABLE record(
recordid NUMBER(5) PRIMARY KEY,
cardid VARCHAR2(10) NOT NULL,
computerid VARCHAR2(10) NOT NULL,
begintime CHAR(19) NOT NULL,
endtime CHAR(19),
fee NUMBER(5,1),
CONSTRAINT record_card_fk FOREIGN KEY(cardid) REFERENCES card(cardid),
CONSTRAINT record_computer_fk FOREIGN KEY(computerid) REFERENCES computer(computerid)
);
中
CONSTRAINT record_card_fk FOREIGN KEY(cardid) REFERENCES card(cardid),
CONSTRAINT record_computer_fk FOREIGN KEY(computerid) REFERENCES computer(computerid）
是什么意思？
