Django模型关系

Question

I'm making the model for my app and I have a question about the relationship of a model.

The Company model has one or more Offices. And the Office has one or more Employees.

class Company(models.Model):
        name = models.CharField(max_length=50)
        mail = models.EmailField(null=True, blank=True)
        NIF = models.CharField(max_length=9, null=True, blank=True)
        def __unicode__(self):
                return self.name

class Office(models.Model):
        company = models.ForeignKey(Company)
        name = models.CharField(max_length=50, default='Main')
        direction = models.CharField(max_length=50)
        def __unicode__(self):
                return self.name

class Employee(models.Model):
        company = models.ForeignKey(Company)
        office = models.ForeignKey(Office)
        name = models.CharField(max_length=50)
        mail = models.EmailField(null=True, blank=True)
        def __unicode__(self):
                return self.name

How I can make a relationship between the employee and the company and office?

Answer 1

Remove the company foreign key from Employee .

class Employee(models.Model):
    office = models.ForeignKey(Office)
    name = models.CharField(max_length=50)
    mail = models.EmailField(null=True, blank=True)
    def __unicode__(self):
            return self.name

As the Office model already has a relationship with Company and Employee has relationship to Office , you can just access it like employee.office.company -

employee_one = Employee.objects.get(pk=1)
company_of_employee_one = employee_one.office.company

If you want to access the data other way around(ie get all offices of a company, get all employees of an office), you can do something like this -

company = Company.objects.get(pk=1)
offices = company.office_set.all()
for office in offices:
    employees = office.employee_set.all()