之前已经创建了一个Student的表,Age有数据类型为Int,现在改为smallint应该( )写。
A.ALTER TABLE student ALTER COLUMN sage smallint
B.ALTER TABLE student ALTER COLUMN age smallint
C.ALTER TABLE student ALTER MODIFY age smallint
D.ALTER TABLE student MODIFY sage smallint
第1题:
A.ALTERTABLEstudentMODIFYsagesmallint
B.ALTERTABLEstudentALTERCOLUMNagesmallint
C.ALTERTABLEstudentALTERMODIFYagesmallint
D.ALTERTABLEstudentALTERCOLUMNsagesmallint
第2题:
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
第3题:
下列说法正确的是()
A.alter table user drop column sex;
B.alter table user add sex varchar(20);
C.alter table user drop sex;
D.alter table user modify id int primary key;
第4题:
将Student.dbf表中jg字段的名称改为籍贯,如下选项中正确的SQL语句是A)ALTER TABLE student ALTER COLUMN jg TO籍贯B)ALTER TABLE student ADD籍贯C(10)C)ALTER TABLE student RENAME jg TO籍贯D)ALTER TABLE student RENAME jg籍贯
第5题:
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);
第6题:
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);
第7题:
根据SQL标准,增加一个新的字段sdate到表student中,该字段为可容纳7个字符的定长字符串,下面哪条语句可以参考表述?()
A insert into student sdate char(7)
B add sdate char(7) to student
C append sdate varchar(7) to table student
D alter table student add sdate varchar(7)
E alter table student add sdate char(7)
F alter table student modify sdate char(7)
第8题:
要给学生信息表(STUDENT)增加一个出生日期字段(日期型),下面正确的是____
A CREATE TABLE STUDENT ADD COLUMN 出生日期 DATETIME
B ALTER TABLE STUDENT ALTER COLUMN 出生日期 DATETIME
C ALTER TABLE STUDENT ADD COLUMN 出生日期 DATETIME
D ALTER TABLE STUDENT SET COLUMN 出生日期 DATETIME
第9题:
假设有student表,可以正确添加字段“平均分数”的命令是( )。
A.ALTER TABLE student ADD平均分数F(6,2)
B.ALTER DBF student ADD平均分数F6,2
C.CHANGE TABLE student ADD平均分数F(6,2)
D.CHANGE TABLE student INSERT平均分数6,2
第10题:
删除student表中“平均成绩”字段的正确SQL命令是( )。
A. DELETE TABLE student DELETE COLUMN平均成绩
B. ALTER TABLE student DELETE COLUMN平均成绩
C. ALTER TABLE student DROP COLUMN平均成绩
D. DELETE TABLE student DROP COLUMN平均成绩