模拟一个单位的人事管理，人事信息主要包括：员工编号、所在部门、职务、薪资等级、薪资、联系方式等内容；部门信息主要包括：部门编号、部门名称等内容。完成以下操作：实现员工信息、部门信息的添加、修改、删除和查询

好的，我们可以采用面向对象的思想，设计一个人事管理系统。以下是一个示例的数据模型和代码实现，仅供参考。

数据模型：

class Department:
    def __init__(self, dept_id, dept_name):
        self.dept_id = dept_id
        self.dept_name = dept_name
        self.employee_list = []

class Employee:
    def __init__(self, emp_id, dept_id, position, salary_level, salary, contact):
        self.emp_id = emp_id
        self.dept_id = dept_id
        self.position = position
        self.salary_level = salary_level
        self.salary = salary
        self.contact = contact

class HRSystem:
    def __init__(self):
        self.departments = {}
        self.employees = {}

    def add_department(self, dept_id, dept_name):
        if dept_id in self.departments:
            print("Department already exists!")
            return
        self.departments[dept_id] = Department(dept_id, dept_name)

    def update_department(self, dept_id, dept_name):
        if dept_id not in self.departments:
            print("Department does not exist!")
            return
        self.departments[dept_id].dept_name = dept_name

    def delete_department(self, dept_id):
        if dept_id not in self.departments:
            print("Department does not exist!")
            return
        del self.departments[dept_id]

    def search_department(self, dept_id):
        if dept_id not in self.departments:
            print("Department does not exist!")
            return None
        return self.departments[dept_id]

    def add_employee(self, emp_id, dept_id, position, salary_level, salary, contact):
        if emp_id in self.employees:
            print("Employee already exists!")
            return
        if dept_id not in self.departments:
            print("Department does not exist!")
            return
        employee = Employee(emp_id, dept_id, position, salary_level, salary, contact)
        self.employees[emp_id] = employee
        self.departments[dept_id].employee_list.append(employee)

    def update_employee(self, emp_id, dept_id, position, salary_level, salary, contact):
        if emp_id not in self.employees:
            print("Employee does not exist!")
            return
        if dept_id not in self.departments:
            print("Department does not exist!")
            return
        employee = self.employees[emp_id]
        employee.dept_id = dept_id
        employee.position = position
        employee.salary_level = salary_level
        employee.salary = salary
        employee.contact = contact

    def delete_employee(self, emp_id):
        if emp_id not in self.employees:
            print("Employee does not exist!")
            return
        employee = self.employees[emp_id]
        self.departments[employee.dept_id].employee_list.remove(employee)
        del self.employees[emp_id]

    def search_employee(self, emp_id):
        if emp_id not in self.employees:
            print("Employee does not exist!")
            return None
        return self.employees[emp_id]

以上代码仅供参考，具体实现可以根据实际需求进行修改。