Employees表和Departments表的定义如下: Employees表: Column Datatype Constraint Emp_id int Primary Key Emp_name varchar Not null Salary int Check (salary between 1000 and 12000) Designamtion varchar Not null Detpartment_id int, foreign key(Department_id) References Departments(Dept_id) on delete cascade Departments表: Column Datatype Constraint Dept_id int Primary Key Dept_name varchar Not null Location varchar Not null 下列说法正确的是: