OCP-1Z0-051 補充題庫 第2題 添加外鍵FOREIGN KEY

一、原題

You need to design a student registration database that contains several tables storing academic

information.

The STUDENTS table stores information about a student. The STUDENT_GRADES table stores

information about the student's grades. Both of the tables have a column named STUDENT_ID.

The STUDENT_ID column in the STUDENTS table is a primary key.

You need to create a foreign key on the STUDENT_ID column of the STUDENT_GRADES table

that points to the STUDENT_ID column of the STUDENTS table. Which statement creates the

foreign key?

A.

CREATE TABLE student_grades (student_id NUMBER(12),

                             semester_end DATE,

                             gpa NUMBER(4,3),

                             CONSTRAINT student_id_fk REFERENCES (student_id) FOREIGN KEY students(student_id));

B.

CREATE TABLE student_grades(student_id NUMBER(12),

                            semester_end DATE,

                            gpa NUMBER(4,3),

                            student_id_fk FOREIGN KEY (student_id) REFERENCES students(student_id));

C.

 CREATE TABLE student_grades(student_id NUMBER(12),

                             semester_end DATE,

                             gpa NUMBER(4,3),

                             CONSTRAINT FOREIGN KEY (student_id) REFERENCES students(student_id));

D.

CREATE TABLE student_grades(student_id NUMBER(12),

                             semester_end DATE,

                             gpa NUMBER(4,3),

                             CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students(student_id));

答案: D

二、題目翻譯

要設計一個包含幾個表的存儲大學生注冊資訊的資料庫。

STUDENTS表儲存學生資訊，STUDENT_GRADES表儲存學生的成績資訊，這兩張表都有一列STUDENT_ID,STUDENTS表中的STUDENT_ID列是主鍵。

現在要在STUDENT_GRADES表上建一個STUDENT_ID列的外鍵，下面哪個是建外鍵的語句?

三、題目解析

這個就是文法問題，查一下文法圖，就可以了。