A. No privileges.B. Only the SELECT privilege.C. Only t……

单项选择题The EMPLOYEES table has these columns: LAST NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: ALTER TABLE EMPLOYEES MODIFY ( SALARY DEFAULT 5000); What is true about your ALTER statement?（）

A. Column definitions cannot be altered to add DEFAULT values.
B. A change to the DEFAULT value affects only subsequent insertions to the table.
C. Column definitions cannot be altered at add DEFAULT values for columns with a NUMBER data type.
D. All the rows that have a NULL value for the SALARY column will be updated with the value 5000.

单项选择题Which substitution variable would you use if you want to reuse the variable without prompting the user each time? （）

A. &
B. ACCEPT
C. PROMPT
D. &&

单项选择题What is true about the WITH GRANT OPTION clause?（）

A. It allows a grantee DBA privileges.
B. It is required syntax for object privileges.
C. It allows privileges on specified columns of tables.
D. It is used to grant an object privilege on a foreign key column.
E. It allows the grantee to grant object privileges to other users and roles.

单项选择题Which constraint can be defines only at the column level? （）

A. UNIQUE
B. NOT NULL
C. CHECK
D. PRIMARY KEY
E. FOREIGN KEY

单项选择题In which scenario would TOP N analysis be the best solution? （）

A. You want to identify the most senior employee in the company.
B. You want to find the manager supervising the largest number of employees.
C. You want to identify the person who makes the highest salary for all employees.
D. You want to rank the top three sales representatives who have sold the maximum number of products.