【2019年8月版本】OCP 071認證考試最新版本的考試原題-第4題

choose two

Exammine the desciption of the PRODUCT DETALS table:

NAME NULL TYPE

---

PRODUCT_ID NOT NULL NUMBER(2)

PRODUCT_NAME NOT NULL VARCHAR2(25)

PRODUCT_PRICE NUMBER(8,2)

EXPIRY_DATE DATE

Which two statements are true?

A) PRODUCT_ID can be assigned the PEIMARY KEY constraint.

B) EXPIRY_DATE cannot be used in arithmetic expressions.

C) EXPIRY_DATE contains the SYSDATE by defalt if no date is assigned to it

D) PRODUCT_PRICE can be used in an arithmetic expression even if it has no value stored in it

E) PRODUCT_PRICE contains the value zero by default if no value is assigned to it.

F) PRODUCT_NAME cannot contain dupicate values.

Answer：AD

(解析：A 答案考的是若是有非空約束還能不能再添加主鍵約束，答案是能夠。number 型的列即便是空值也能夠出如今數學表達式上，可是最後的結果會是空值。)