多项选择题
Which are DML statements? （）
A. COMMIT…
B. MERGE…
C. UPDATE…
D. DELETE…
E. CREATE…
F. DROP…
相关考题
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单项选择题
Examine the structures of the EMPLOYEES and TAX tables. You need to find the percentage tax applicable for each employee. Which SQL statement would you use?（）
A. SELECT employee_id, salary, tax_percent FROM employees e, tax t WHERE e.salary BETWEEN t.min_salary AND t.max_salary;
B. SELECT employee_id, salary, tax_percent FROM employees e, tax t WHERE e.salary > t.min_salary, tax_percent
C. SELECT employee_id, salary, tax_percent FROM employees e, tax t WHERE MIN(e.salary) = t.min_salary AND MAX(e.salary) = t.max_salary
D. You cannot find the information because there is no common column between the two tables. -
单项选择题
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); -
单项选择题
You are the DBA for an academic database. You need to create a role that allows a group of users to modify existing rows in the STUDENT_GRADES table.Which set of statements accomplishes this?（）
A. CREATE ROLL registrar; GRANT MODIFY ON student_grant TO registrar; GRANT registrar to user 1, user2, user3
B. CREATE NEW ROLE registrar; GRANT ALL ON student_grant TO registrar; GRANT registrar to user 1, user2, user3
C. CREATE ROLL registrar; GRANT UPDATE ON student_grant TO registrar; GRANT ROLE to user1, user2, user3
D. CREATE ROLL registrar; GRANT UPDATE ON student_grant TO registrar; GRANT registrar to user 1, user2, user3;
E. CREATE registrar; GRANT CHANGE ON student_grant TO registrar; GRANT registrar;
