Django通过集合查询

Question

我是Django的新手，我被困在多个集合的查询中。

我有三种模式;

class Project(models.Model): 
    name = models.CharField(max_length = 100) 

class AppointmentGroup(models.Model): 
    name = models.CharField(max_length = 100) # not used in design.. delete when not used at the end of the project 
    project = models.ForeignKey(Project) 
    location = models.ForeignKey(Location) 

class Appointment(models.Model): 
    appointment_group = models.ForeignKey(AppointmentGroup) 
    start_date = models.DateTimeField() 
    end_date = models.DateTimeField() 

现在我想设置一个返回对象，只设置具有特定年份内约会的项目。而且项目对象中的约会集对象仅包含那年的那些对象！

这是很容易做的Django查询或必须循环通过项目一个接一个，并检查日期的所有约会？

Answer 1

我猜，约会模型是一些如何与您的项目相关，你刚刚离开。

你可能想使用range和lookups that span relationships：

import datetime 
start = datetime.date(2010, 1, 1) 
end = datetime.date(2010, 12, 31) 
projects_in_2010 = Projects.objects.filter(appointmentgroup__appointment__start_date__range(start, end)) 

Answer 2

试试这个

AppointmentGroup.objects.filter(appoinment_set__start_date__year=2011, appoinment_set__end_date__year=2011)