在关系SC(student_id,student_name,course_id,grade)中，有 student_id,course_id→grade student_id→student_name 关系SC最高达到______范式。A．不满足B．1NFC．2NFD．3NF

题目

在关系SC(student_id,student_name,course_id,grade)中，有 student_id,course_id→grade student_id→student_name 关系SC最高达到______范式。

A．不满足

B．1NF

C．2NF

D．3NF

相似考题

1.第 26～27 题基于以下说明。 设有三个关系：学生关系S(SNO，SNAME，AGE，SEX)(分别代表学生的学号、姓名、年龄、性别)学习关系SC(SNO，CNO，GRADE)(分别代表学生的学号、课程编号、成绩)课程关系C(CNO，CNAME，TEACHER)(分别代表课程的编号、课程名、任课教师)第26题：“从学习关系SC中检索无成绩的学生学号”的SQL语句是（ ）。A．SELECT sno FROM sc WHERE grade=NULLB．SELECT sno FROM sc WHERE grade ISC．SELECT Sno FROM sc WHERE grade IS NULLD．SELECT sno FROM sc WHERE grade=

2.设有关系模式：SC(sno，cno，grade)，各属性含义依次是学号、课程号、分数。将关系SC中所有选修课程号为‘DB’的学生的分数增加10分，正确的SQL命令是A．ALTER TABLE SC SET GRADE+10 WHERE CNO=’DB’B．ALTER TABLE SC SET GRADE=GRADE+10 WHERE CNO=’DB’C．UPDATE SC SET GRADE+10 WHERE CNO=’DB’D．UPDATE SC SET GRADE=GRADE+10 WHERE CNO=’DB’

3.在关系SC中，查询学习课程号为′DB′，且成绩在60至90之间的学生学号的正确的 SQL命令是A．SELECT SNO FROM SC WHERE CNO=′DB′AND GRADE DETWEEN 60 AND 90B．SELECT SNO FROM SC WHERE CNO=′DB′OR GRADE BETWEEN 60 AND 90C．SELECT SNO FROM SC WHERE CNO=′DB′AND GRADE＞=60 AND 90D．SELECT SNO FROM SC WHERE CNO=′DB′AND GRADE＜=60 AND GRADE＞=90

4.在关系SC中，查询学习课程号为\'DB\'，且成绩在60至90之间的学生学号的正确的SQL命令是（ ）。A．SELECT SNO FROM SC WHERE CNO='DB'AND GRADE BETWEEN 60 AND 90B．SELECT SNO FROM SC WHERE CN0='DB' 0R GRADE BETWEEN 60 AND 90C．SELECT SNO FROM SC WHERE CNO='DB'AND GRADE>=60 AND 90D．SELECT SNO FROM SC WHERE CNO='DB'AND GRADE<=60 AND GRADE>=90

参考答案和解析
正确答案：B
更多“在关系SC(student_id,student_name,course_id,grade)中,有student_id,course_id→gradestudent_id ”相关问题

  • 第1题：

    在“学生—选课—课程”数据库中的两个关系如下：

    S(SNO,SNAME,SEX,AGE)

    SC(SNO,CNO,GRADE)

    则与SQL命令SELECT s.sname，sC.grade FROM s, sc WHERE s.sno＝s sC.sno等价的关系代数表达式是【 】。


    正确答案：πs.sname sc. Grade^(S SC)
    πs.sname, sc. Grade^(S SC) 解析：SQL命令SELECT s.sname，s sC.grade FROM s, sc WHERE s.sno=s sC.sno完成的运算实际上是将关系S与关系SC进行自然连接运算，然后再进行投影。

  • 第2题：

    You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty. Which statement accomplishes this task?()

    A. ALTER TABLE students ADD PRIMARY KEY _ id;

    B. ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);

    C. ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;

    D. ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);

    E. ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);


    参考答案：D

  • 第3题：

    The STUDENT_GRADES table has these columns:The register has requested a report listing the students‘ grade point averages (GPA), sorted from highest grade point average to lowest within each semester, starting from the earliest date. Which statement accomplishes this?（）

    A. SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester_end DESC, gpa DESC;

    B. SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester_end ASC, gpa ASC;

    C. SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester_end, gpa DESC;

    D. SELECT student_id, semester_end, gpa FROM student_grades ORDER BY gpa DESC, semester_end DESC;

    E. SELECT student_id, semester_end, gpa FROM student_grades ORDER BY gpa DESC, semester_end ASC;


    参考答案：C

  • 第4题：

    在关系SC中，查询学习课程号为'OB'，且成绩在60至90之间的学生学号的正确的 SQL命令是

    A．SELECT SNO FROMSC WHERE CNO＝'DB' AND GRADE BETWEEN 60 AND 90

    B．SELECT SNO FROM SC WHERE CNO＝'DB' OR GRADE BETWEEN 60 AND 90

    C．SELECT SNO FROM SC WHERE CNO＝'DB' AND GRADE＞=60 AND 90

    D．SELECTSNO FROM SCWHERECNO＝'DB' AND GRADE＜＝60 AND GRADE＞＝90


    正确答案：A
    解析：GRADEBETWEEN60AND90等价于GRADE＞=60ANDGRADE=90。

  • 第5题：

    若要使所有学科80分以上的成绩都增加5%, 80至60分的成绩都增加10%，应如何更新数据库（ ）。 A．UPDATE SC SET GRADE=GRADE*1．05 WHERE SC．GRADE>=80 UPDATE SC SET GRADE=GRADE* 1．10 WHERE SC．GRADE>=60 AND SC．GRADE <=80 B．UPDATE SC SET GRADE=GRADE* 1．10 WHERE SC．GRADE>=60 AND SC．GRADE<=80 UPDATE SC SET GRADE=GRADE* 1．05 WHERE SC．GRADE>=80 C．UPDATE SC SET GRADE=GRADE* 1．05 WIRE SC．GRADE>=80 AND SET GRADE =GRADE* 1．10 WHARE SC．GRADE>=60 D．UPDATE SC SET GRADE=GRADE* 1．10 WHERE SC．GRADE>=60 AND SC．GRADE <=80 AND SET GRADE=GRADE* 1．05 WHERE SC．GRADE>=80


    正确答案：A
    Update 语句用于修改表中的数据,语法：UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值，根据语法，表名称应该为SC，GRADE=GRADE*1．05，条件为SC．GRADE>=80，后面的60到80分的同理。

  • 第6题：

    把对关系SC的属性GRADE的修改权授予用户ZHAO的SQL语句是 （）

    • A、GRANT GRADE ON SC TO ZHAO                   
    • B、GRANT UPDATE ON SC TO ZHAO 
    • C、GRANT UPDATE (GRADE) ON SC TO ZHAO         
    • D、GRANT UPDATE ON SC (GRADE) TO ZHAO

    正确答案:C

  • 第7题：

    The STUDENT_GRADES table has these columns: STUDENT_ID NUMBER(12) SEMESTER_END DATE GPA NUMBER(4,3) The register has requested a report listing the students' grade point averages (GPA), sorted from highest grade point average to lowest within each semester, starting from the earliest date. Which statement accomplishes this?（）

    • A、SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester_end DESC, gpa DESC;
    • B、SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester _end, ASC,gpa ASC;
    • C、SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester _end, gpa DESC;
    • D、SELECT student_id, semester_end, gpa FROM student_grades ORDER BY gpa DESC,semester_end DESC;
    • E、SELECT student_id, semester_end, gpa FROM student_grades

    正确答案:C

  • 第8题：

    单选题
    Examine the structure of the STUDENTS table: STUDENT_ID NUMBER NOT NULL, Primary Key STUDENT_NAME VARCHAR2(30) COURSE_ID VARCHAR2(10) NOT NULL MARKS NUMBER START_DATE DATE FINISH_DATE DATE You need to create a report of the 10 students who achieved the highest ranking in the course INT SQL and who completed the course in the year 1999. Which SQL statement accomplishes this task? （）
    A

    SELECT student_ id, marks, ROWNUM Rank FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99 AND course_id = 'INT_SQL' ORDER BY mark DESC;

    B

    SELECT student_id, marks, ROWID Rank FROM students WHERE ROWID <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY mark;

    C

    SELECT student_id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC- 99' AND course_id = 'INT_SQL' ORDER BY mark DESC;

    D

    SELECT student_id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students WHERE (finish_date BETWEEN '01-JAN-99 AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY marks DESC) WHERE ROWNUM <= 10;

    E

    SELECT student id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students ORDER BY marks) WHERE ROWNUM <= 10 AND finish date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course _ id 'INT_SQL';


    正确答案： C
    解析： 暂无解析

  • 第9题：

    单选题
    Which statement explicitly names a constraint?（）
    A

    ALTER TABLE student_grades ADD FOREIGN KEY (student_id) REFERENCES students (student_id);

    B

    ALTER TABLE student_grades ADD CONSTRAINT NAME = student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);

    C

    ALTER TABLE student_grades ADD CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);

    D

    ALTER TABLE student grades ADD NAMED CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);

    E

    ALTER TABLE student grades ADD NAME student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);


    正确答案： D
    解析： 暂无解析

  • 第10题：

    单选题
    You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty. Which statement accomplishes this task?（）
    A

    ALTER TABLE students ADD PRIMARY KEY _ id;

    B

    ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);

    C

    ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;

    D

    ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);

    E

    ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);


    正确答案： D
    解析： 暂无解析

  • 第11题：

    单选题
    The STUDENT_GRADES table has these columns: STUDENT_ID NUMBER(12) SEMESTER_END DATE GPA NUMBER(4,3) The registrar requested a report listing the students' grade point averages (GPA) sorted from highest grade point average to lowest. Which statement produces a report that displays the student ID and GPA in the sorted order requested by the registrar?（）
    A

    SELECT student_id, gpa FROM student_grades ORDER BY gpa ASC;

    B

    SELECT student_id, gpa FROM student_grades SORT ORDER BY gpa ASC;

    C

    SELECT student_id, gpa FROM student_grades SORT ORDER BY gpa;

    D

    SELECT student_id, gpa FROM student_grades ORDER BY gpa;

    E

    SELECT student_id, gpa FROM student_grades SORT ORDER BY gpa DESC;

    F

    SELECT student_id, gpa FROM student_grades ORDER BY gpa DESC;


    正确答案： B
    解析： 暂无解析

  • 第12题：

    单选题
    You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty. Which statement accomplishes this task?（）
    A

    ALTER TABLE students ADD PRIMARY KEY student_id;

    B

    ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);

    C

    ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;

    D

    ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);

    E

    ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);


    正确答案： A
    解析： 暂无解析

  • 第13题：

    The STUDENT_GRADES table has these columns:STUDENT_ID NUMBER(12)SEMESTER_END DATEGPA NUMBER(4,3)The registrar requested a report listing the students‘ grade point averages (GPA) sorted from highest grade point average to lowest.Which statement produces a report that displays the student ID and GPA in the sorted order requested by the registrar? （）

    A. SELECT student_id, gpa FROM student_grades ORDER BY gpa ASC;

    B. SELECT student_id, gpa FROM student_grades SORT ORDER BY gpa ASC;

    C. SELECT student_id, gpa FROM student_grades SORT ORDER BY gpa;

    D. SELECT student_id, gpa FROM student_grades ORDER BY gpa;

    E. SELECT student_id, gpa FROM student_grades SORT ORDER BY gpa DESC;

    F. SELECT student_id, gpa FROM student_grades ORDER BY gpa DESC;


    参考答案：F

  • 第14题：

    Which statement explicitly names a constraint? ()

    A. ALTER TABLE student_grades ADD FOREIGN KEY (student_id) REFERENCES students (student_id);

    B. ALTER TABLE student_grades ADD CONSTRAINT NAME = student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);

    C. ALTER TABLE student_grades ADD CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);

    D. ALTER TABLE student grades ADD NAMED CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);

    E. ALTER TABLE student grades ADD NAME student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id);


    参考答案：C

  • 第15题：

    设有如下关系： SC(sno，cname，grade)(各属性含义分别为学生的学号、课程名称、成绩)现要将所 有学生的课程成绩增加10分，以下能正确地完成此操作的SQL命令是( )。

    A．MODIFY sc SET grade+10

    B．UPDATE sc SET grade+10

    C．MODIFY sc SET grade=grade+10

    D．UPDATE sc SET grade=grade+10


    正确答案：D

  • 第16题：

    在“学生—选课—课程”数据库中的两个关系如下：

    s(sno,sname,sex,age)

    sc(sno,cno,grade)

    则关系代数表达式πs.sname,grade()等价的SQL命令是SELECT s.sname,sc.grade FROM s,sc WHERE______AND s.age＞20


    正确答案：s.sno=sc.sno
    s.sno=sc.sno 解析：将关系S和SC进行自然连接，其自然连接的条件是s.sno=sc.sno。

  • 第17题：

    在关系SC(student_id，student_name，course_id, grade)中，有student_id，course_id→ gradesmdent_id→student_name关系SC最高达到( )范式。

    A．不满足

    B．1NF

    C．2NF

    D．3NF


    正确答案：B

  • 第18题：

    You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty. Which statement accomplishes this task?（）

    • A、ALTER TABLE students ADD PRIMARY KEY _ id;
    • B、ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);
    • C、ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;
    • D、ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
    • E、ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);

    正确答案:D

  • 第19题：

    单选题
    Examine the structure of the STUDENTS table: STUDENT_ID NUMBER NOT NULL, Primary Key STUDENT_NAME VARCHAR2(30) COURSE_ID VARCHAR2(10) NOT NULL MARKS NUMBER START_DATE DATE FINISH_DATE DATE You need to create a report of the 10 students who achieved the highest ranking in the course INT SQL and who completed the course in the year 1999. Which SQL statement accomplishes this task?（）
    A

    SELECT student_ id, marks, ROWNUM Rank FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99 AND course_id = 'INT_SQL' ORDER BY mark DESC;

    B

    SELECT student_id, marks, ROWID Rank FROM students WHERE ROWID <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY mark;

    C

    SELECT student_id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC- 99' AND course_id = 'INT_SQL' ORDER BY mark DESC;

    D

    SELECT student_id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students WHERE (finish_date BETWEEN '01-JAN-99 AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY marks DESC) WHERE ROWNUM <= 10;

    E

    SELECT student id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students ORDER BY marks) WHERE ROWNUM <= 10 AND finish date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course _ id 'INT_SQL';


    正确答案： B
    解析： 暂无解析

  • 第20题：

    单选题
    Examine the structure of the STUDENTS table: STUDENT_ID NUMBER NOT NULL, Primary Key STUDENT_NAME VARCHAR2(30) COURSE_ID VARCHAR2(10) NOT NULL MARKS NUMBER START_DATE DATE FINISH_DATE DATE You need to create a report of the 10 students who achieved the highest ranking in the course INT SQL and who completed the course in the year 1999. Which SQL statement accomplishes this task?（）
    A

    SELECT student_ id, marks, ROWNUM Rank FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY marks DESC;

    B

    SELECT student_id, marks, ROWID Rank FROM students WHERE ROWID <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY marks;

    C

    SELECT student_id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course_id = 'INT_SQL' ORDER BY marks DESC);

    D

    SELECT student_id, marks, ROWNUM Rank FROM (SELECT student_id, marks FROM students ORDER BY marks DESC) WHERE ROWNUM <= 10 AND finish_date BETWEEN '01-JAN-99' AND '31-DEC-99' AND course _ id ='INT _ SQL';


    正确答案： D
    解析： 暂无解析

  • 第21题：

    单选题
    The STUDENT_GRADES table has these columns STUDENT_ID NUMBER(12) SEMESTER_END DATE GPA NUMBER(4,3) Which statement finds students who have a grade point average (GPA) greater than 3.0 for the calendar year 2001?（）
    A

    SELECT student_id, gpa FROM student_grades WHERE semester_end BETWEEN '01-JAN-2001' AND '31-DEC-2001' OR gpa > 3.;

    B

    SELECT student_id, gpa FROM student_grades WHERE semester_end BETWEEN '01-JAN-2001' AND '31-DEC-2001' AND gpa gt 3.0;

    C

    SELECT student_id, gpa FROM student_grades WHERE semester_end BETWEEN '01-JAN-2001' AND '31-DEC-2001' AND gpa > 3.0;

    D

    SELECT student_id, gpa FROM student_grades WHERE semester_end > '01-JAN-2001' OR semester_end < '31-DEC-2001' AND gpa >=s 3.0;


    正确答案： C
    解析： 暂无解析

  • 第22题：

    单选题
    The STUDENT_GRADES table has these columns: STUDENT_ID NUMBER(12) SEMESTER_END DATE GPA NUMBER(4,3) The register has requested a report listing the students' grade point averages (GPA), sorted from highest grade point average to lowest within each semester, starting from the earliest date. Which statement accomplishes this?（）
    A

    SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester_end DESC, gpa DESC;

    B

    SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester _end, ASC,gpa ASC;

    C

    SELECT student_id, semester_end, gpa FROM student_grades ORDER BY semester _end, gpa DESC;

    D

    SELECT student_id, semester_end, gpa FROM student_grades ORDER BY gpa DESC,semester_end DESC;

    E

    SELECT student_id, semester_end, gpa FROM student_grades


    正确答案： C
    解析： 暂无解析

  • 第23题：

    单选题
    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));


    正确答案： D
    解析： 暂无解析

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