将返回语法错误
将向EMPLOYEES表添加约束条件
将改写EMPLOYEES表的一个现有约束条件
将启用EMPLOYEES表的一个现有约束条件
第1题:
为“部门”表增加一个“人数”字段,类型为整型,正确的语句是( )。
A.ALTER TABLE部门ALTER人数I
B.ALTER TABLE部门ALTER FIELDS人数I
C.ALTER TABLE部门ADD人数I
D.ALTER TABLE部门ADD FIELDS人数I
第2题:
A. ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;
B. ALTER TABLE customers MODIFY CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;
C. ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn NOT NULL;
D. ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn IS NOT NULL;
E. ALTER TABLE customers MODIFY name CONSTRAINT cust_name_nn NOT NULL;
F. ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name NOT NULL;
第3题:
在SQL Server 2000中,设有职工表(职工号, 职工名, 电子邮箱),现要限制电子邮箱的最后几位的取值为“@abc.com”,且“@”前至少有一位字符。下列添加约束的语句正确的是
A.ALTER TABLE职工表 ADD CONSTRAINT chk_email CHECK(电子邮箱LIKE '_%@abc.com')
B.ALTER TABLE职工表 ADD CONSTRAINT chk_email CHECK(电子邮箱 = '_%@abc.com')
C.ALTER TABLE职工表 ADD CONSTRAINT chk_email CHECK(电子邮箱LIKE '_@abc.com')
D.ALTER TABLE职工表 ADD CONSTRAINT chk_email CHECK(电子邮箱 = '_@abc.com')
第4题:
为表TEST中ID列添加主键约束的语法是()
第5题:
A. ALTER TABLE table_name ENABLE constraint_name;
B. ALTER TABLE table_name STATUS = ENABLE CONSTRAINT constraint _ name;
C. ALTER TABLE table_name ENABLE CONSTRAINT constraint _ name;
D. ALTER TABLE table_name TURN ON CONSTRAINT constraint _ name;
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:
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8题:
以下语句错误的是( )
A. alter table emp delete column addcolumn;
B. alter table emp modify column addcolumn char(10);
C.alter table emp change addcolumn addcolumn int;
D. alter table emp add column addcolumn int;
第9题:
为“部门”表增加一个“人数”字段,类型为整型,正确的语句是( )。
A.ALTER TABLE部门ALTER人数1
B.ALTER TABLE部门ALTER FIELDS人数l
C.ALTER TABLE部门ADD人数l
D.ALTER TABLE部门ADDFIELDS人数l
第10题:
评估以下语句: ALTER TABLE employees ADD CONSTRAINT employee_id PRIMARY KEY; 该语句将返回以下哪种结果()