Question

考虑以下两个描述某个组织的员工和部门的关系模式（假设所有名称都是唯一的）。

EMPLOYEES (EmployeeName, Salary, DeptName)

DEPARTMENTS (DeptName, ManagerName, City)

在架构级别定义一个约束（SQL断言），该约束指定位于“旧金山”的任何部门的员工的工资都不超过“管理”部门中任何员工的工资。

我的方法：

create assertion CHECK_SALARY as CHECK
(   

not exists (select * from EMPLOYEES

where select salary from EMPLOYEES

where EMPLOYEES.DeptName = 'San Fransisco' <

select salary from EMPLOYEES

where EMPLOYEES.DeptName = 'Management'

)

这是我写的东西，但它没有正常工作，任何建议表示赞赏

Answer 1

尝试这样的事情：

CREATE ASSERTION check_salary AS CHECK (   
  NO EXTISTS ( SELECT * FROM employees
               WHERE ( SELECT MAX(salary) FROM employees
                       WHERE "DeptName" = 'San Fransisco' )
                   < ( SELECT MIN(salary) FROM employees
                       WHERE "DeptName" = 'Management' ) )
);

Answer 2

试试这个。

CREATE ASSERTION check_salary AS CHECK (NO EXTISTS ( SELECT * FROM Employees ee, departments dd WHERE  ee.dept_name = dd.dept_name AND dd.city = 'San Francisco' AND ee.salary < (SELECT Max(salary_amount) FROM Employees e, Departments d WHERE e.dept_name =d.dept_name AND d.Dept_name = 'Management') ));

SQL断言语句

2 个答案: