Django的 - 防止日期範圍重疊

Question

class Session(models.Model): 
    tutor = models.ForeignKey(User) 
    start_time = models.DateTimeField() 
    end_time = models.DateTimeField() 

什麼是始終防止start_time重疊end_time的最佳方式？

Answer 1

首先，你應該在形式層面做到這一點，看到Cleaning and validating fields that depend on each other有關如何執行此操作，它應該是這樣的：

def clean(self): 
    cleaned_data = super(YourForm, self).clean() 
    if cleaned_data['start_time'] > cleaned_data['end_time']: 
     raise forms.ValidationError(_(u'Start time must be before end time')) 

此外，您還可以在保存低水平強制執行方法或在pre_savesignal：

from django.db.models import signals 

class StartTimeAfterEndTimeException(Exception): 
    def __init__(self, model): 
     super(StartTimeAfterEndTimeException, self).__init__(
      'Start time %s should not be after end time %s' % (
       model.start_time, model.end_time)) 

def session_force_end_time(sender, instance, **kwargs): 
    if instance.start_time >= instance.end_time: 
     raise StartTimeAfterEndTimeException(instance) 
signals.pre_save.connect(session_force_end_time, sender=Session) 

但是，這是相當低的水平，所以它不是用戶友好的。