多选题Examine the description of the MARKS table: STD_ID NUMBER(4) STUDENT_NAME VARCHAR2(30) SUBJ1 NUMBER(3) SUBJ2 NUMBER(3) SUBJ3 NUMBER(3) SUBJ1, SUBJ2, and SUBJ3 indicate the marks (grades) obtained by a student in the three subjects. Which two statements

第1题：

第2题：

Examine the description of the EMPLOYEES table: EMP_ID NUMBER(4) NOT NULL LAST_NAME VARCHAR2(30) NOT NULL FIRST_NAME VARCHAR2(30) DEPT_ID NUMBER(2) Which statement produces the number of different departments that have employees with last name Smith?（）

• A、SELECT COUNT(*) FROM employees WHERE last_name='Smith';
• B、SELECT COUNT(dept_id) FROM employees WHERE last_name='Smith';
• C、SELECT DISTINCT(COUNT(dept_id)) FROM employees WHERE last_name='Smith';
• D、SELECT COUNT(DISTINCT dept_id) FROM employees WHERE last_name='Smith';
• E、SELECT UNIQUE(dept_id) FROM employees WHERE last_name='Smith';

第3题：

第4题：

Examine the following command: CREATE TABLE (prod_id number(4), Prod_name varchar2 (20), Category_id number(30), Quantity_on_hand number (3) INVISIBLE); Which three statements are true about using an invisible column in the PRODUCTS table?（）

• A、The %ROWTYPE attribute declarations in PL/SQL to access a row will not display the invisible column in the output.
• B、The DESCRIBE commands in SQL *Plus will not display the invisible column in the output.
• C、Referential integrity constraint cannot be set on the invisible column.
• D、The invisible column cannot be made visible and can only be marked as unused.
• E、A primary key constraint can be added on the invisible column.

第5题：

Which statement accomplish this? （）

• A、CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status VARCHAR2 (10), date_ordered DATE = SYSDATE);
• B、CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status VARCHAR2 (10), date_ordered DATE DEFAULT SYSDATE);
• C、CREATE OR REPLACE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status VARCHAR2 (10), date_ordered DATE DEFAULT SYSDATE);
• D、CREATE OR REPLACE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status NUMBER (10), date_ordered DATE = SYSDATE);
• E、CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status NUMBER (10), date_ordered DATE = SYSDATE);
• F、CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status NUMBER (10), date_ordered DATE DEFAULT SYSDATE);

第6题：

Examine the description of the MARKS table: STD_ID NUMBER(4) STUDENT_NAME VARCHAR2(30) SUBJ1 NUMBER(3) SUBJ2 NUMBER(3) SUBJ3 NUMBER(3) SUBJ1, SUBJ2, and SUBJ3 indicate the marks (grades) obtained by a student in the three subjects. Which two statements are valid? （）

• A、SELECT SUM(subj1, subj2, subj3) FROM marks;
• B、SELECT SUM(subj1 + subj2 + subj3) FROM marks;
• C、SELECT SUM(subj1), SUM(subj2), SUM(subj3) FROM marks;
• D、SELECT MAX(subj1, subj2, subj3) FROM marks;
• E、SELECT MINIMUM(subj1) FROM marks;
• F、SELECT COUNT(std_id) FROM marks WHERE subj1 >= AVG(subj1);

第7题：

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 student (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 student (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));

第8题：

第9题：

Examine the command that is used to create a table：  SQL> CREATE TABLE orders（oid NUMBER（6） PRIMARY KEY， odate DATE， ccode NUMBER（6）， oamt NUMBER（10，2）） TABLESPACE users；  Which two statements are true about the effect of the above command） （）

• A、A CHECK constraint is created on the OID column.
• B、A NOT NULL constraint is created on the OID column.
• C、The ORDERS table is the only object created in the USERS tablespace.
• D、The ORDERS table and a unique index are created in the USERS tablespace.
• E、The ORDERS table is created in the USERS tablespace and a unique index is created on the OIDcolumn in the SYSTEM tablespace.

第10题：

The STUDENT_GRADES table has these columns: STUDENT_ID NUMBER(12) SEMESTER_END DATE GPA NUMBER(4,3) Which statement finds the highest grade point average (GPA) per semester?（）

• A、SELECT MAX(gpa) FROM student_grades WHERE gpa IS NOT NULL;
• B、SELECT (gpa) FROM student_grades GROUP BY semester_end WHERE gpa IS NOT NULL;
• C、SELECT MAX(gpa) FROM student_grades WHERE gpa IS NOT NULL GROUP BY semester_end;
• D、SELECT MAX(gpa) GROUP BY semester_end WHERE gpa IS NOT NULL FROM student_grades;
• E、SELECT MAX(gpa) FROM student_grades GROUP BY semester_end WHERE gpa IS NOT NULL;