【Oracle 12c】最新CUUG OCP-071考试题库(60题)
60、(16-10) choose the best answer: 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 RIUNBER(3) CHECK (qty BETWEEN 100 AND 200), expiry_date date CHECK (expiry_date > SYSDATE), CONSTRAINT it_pk PRIMARY REY (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. A) You cannot use SYSDATE in the condition of a CHECK constraint. B) You cannot use the NEXTVAL sequence value as a DEFAULT value for a column. C) You cannot use the BETWEEN clause in the condition of a CHECK constraint. D) You cannot use ORD_NO and ITEM_NO columns as a composite primary key because ORD_NO is also the FOREIGN KEY. Answer:A (check 约束中明确要求不能: 参考 CURRVAL,NEXTVAL,LEVEL,和 ROWNUM 这样的伪列 调用 SYSDATE,UID,USER,和 USERENV 函数 参考其它列值的查询 ) (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |