我读过一篇9年前写的问答，这里有链接：实体框架-工作单元、存储库和IDisposable -堆栈溢出
这表明它应该实现IDisposable。但YouTube上发布的其他视频没有。它现在应该实现IDisposable接口吗？
当没有实体具有外键关联的事务时，如何回滚？

public class Employee
{
    public long Id { get; set; }
    public string Name { get; set; }
    public long DepartmentId { get; set; }
}

public class Department
{
    public long Id { get; set; }
    public string Name { get; set; }
}

public void AddDepartmentAndEmployees()
{
    var department = new Department { Name = "Dev" };

    var employees = new List<Employee> 
    { 
       new Employee { Name = "Jack" },
       new Employee { Name = "Tim" },
    }

    _departmentRepository.Add(department);
    _departmentRepository.SaveChange();

    employees.All(e => e.DepartmentId = department.Id );
    // if there throw a unknown exception
    // and how can i roll back?
    _employeeRespository.AddRange(employees);
    _departmentRepository.SaveChange();
}

解决以上两个问题。
很抱歉我的英语不好，但是我已经尽力了。