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ocp 11g认证考试051题库解析：第31题

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ocp 11g认证考试051题库解析：第31题，完整题库请点击这里联系老师咨询了解

31. Evaluate the following SQL commands:

SQL>CREATE SEQUENCE ord_seq

INCREMENT BY 10

START WITH 120

MAXVALUE 9999

NOCYCLE;

SQL>CREATE TABLE ord_items

(ord_no NUMBER(4)DEFAULT ord_seq.NEXTVAL NOT NULL,

item_no NUMBER(3),

qty NUMBER(3) CHECK (qty BETWEEN 100 AND 200),

expiry_date date CHECK (expiry_date > SYSDATE),

CONSTRAINT it_pk PRIMARY KEY (ord_no,item_no),

CONSTRAINT ord_fk FOREIGN KEY(ord_no) REFERENCES orders(ord_no));

The command to create a table fails. Identify the reason for the SQL statement failure? (Choose all that

apply.)

A. You cannot use SYSDATE in the condition of a CHECK constraint.

B. You cannot use the BETWEEN clause in the condition of a CHECK constraint.

C. You cannot use the NEXTVAL sequence value as a DEFAULT value for a column.

D. You cannot use ORD_NO and ITEM_NO columns as a composite primary key because ORD_NO is also the FOREIGN KEY.

Answer: AC

答案解析：

A 、SYSDATE不能用在CHECK约束中，对

B、BETWEEN可以用在约束中，B错

C、NEXTVAL不能用作默认值，C对

D、外键约束和字段可以和本表组合成主键，D错。

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