在数据库中，删除数据表student的命令是什么？ (1.0分) [单选.] A. delete table student B. delete student C. drop student D. drop table student

从student表删除年龄大于30的记录的正确SQL命令是（ ）。

A.DELETE FOR年龄>30

B.DELETE FROM student WHERE年龄>30

C.DELETE student FOR年龄>30

D.DELETE student WHERE年龄>30

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 storesinformation 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 thatpoints 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));

删除视图STUDENT的命令是( )。

A．DELETE STUDENT VIEW

B．DELETE STUDETN

C．DROP STUDENT VIEW

D．DROP VIEW STUDENT

A. MANAGER must be a role.

B. It allows the MANAGER to pass the specified privileges on to other users.

C. It allows the MANAGER to create tables that refer to the STUDENT_GRADES table.

D. It allows the MANAGER to apply all DML statements on the STUDENT_GRADES table.

E. It allows the MANAGER the ability to select from, insert into, and update the STUDENT_GRADES table.

F. It allows the MANAGER the ability to select from, delete from, and update the STUDENT_GRADES table.

根据SQL标准，要删除表student中所有数据，但不将表student的定义一起删除，下面哪个语句可以适用?()

A delete from student

B delete all from student

C delete * from student

D drop table student

由于学号(SN)为00291的学生已毕业，欲在关系“Student”中删除该学生的所有信息，用元组关系演算语言实现应为(53)。

A．GET W(Student): Student. SN = 00291' DELETE W

B．GET W: Student. SN = 00291'in Student DELETE W

C．HOLD W(student): Student. SN = 00291' DELETE W

D．HOLD W: Student. SN = 00291'in Student DELETE W

根据SQL标准，删除表student中对字段sno的唯一性约束，应该使用下面哪条语句? ()

A drop sno from table student

B alter table student drop sno

C alter table student drop unique(sno)

D alter table student drop sno unique

如果要删除Student数据库中的Information表，可以使用下列哪个命令?一——

A．ALTER TABLE Information

B．TRUNCATE TABLE Information

C．DROP。TABLE Information

D．DELETE TABLE Information

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);

删除视图STUDENT的命令是( )。

A．DELETE STUDENTVIEW

B．DELETE STUDETN

C．DROP STUDENTVIEW

D．DROPVIEW STUDENT