如何在Django自动创建的ManyToMany通过模型和手动定义的模型之间进行调整？ [英] How to distuingish between Django's automatically created ManyToMany through-models and manually defined ones?

问题描述

说我们有模型：

 从django.db导入模型
 
 class AutomaticModel（models $ M $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = '通过模型'）
 
 class OtherModel（models.Model）：
 pass 
 
 class ThroughModel（models.Model）：
 pblm = models.ForeignKey （'ManualModel'）
 other = models.ForeignKey（'OtherModel'）
  

此后我们可以通过

AutomaticModel._meta.get_field（'others'）访问通过模型。rel.through 和

  ManualModel._meta.get_field（'others'）。rel.through 
  / pre> 
 
 
问题：
 
 
 
如果给定 AutomaticModel 或 ManualModel （或他们的'其他'字段），如何确定是否通过odel是自动或手动创建的。
 
 
 
当然，除了测试名称，但它不符合一般情况 - 也检查models.py的内容也有一点错误倾向。 
 
 
 
任何线索？
解决方案
那么，南方开发人员似乎知道：模型是自动生成的，如果
 ＃Django 1.0 / 1.1 
（not field.rel.through）
或
＃Django 1.2+ 
 getattr（getattr（field.rel。通过_meta，无），auto_created，False）
  
 Woohoo！
 
Say we have models:
from django.db import models

class AutomaticModel(models.Model):
    others = models.ManyToManyField('OtherModel')

class ManualModel(models.Model):
    others = models.ManyToManyField('OtherModel', through='ThroughModel')

class OtherModel(models.Model):
    pass

class ThroughModel(models.Model):
    pblm = models.ForeignKey('ManualModel')
    other = models.ForeignKey('OtherModel')
After this we can access the through models via 

AutomaticModel._meta.get_field('others').rel.through and
ManualModel._meta.get_field('others').rel.through
Problem:

If given either of AutomaticModel or ManualModel (or their 'others' fields), how to determine, whether the through-model was created automatically or manually.

Of course, except for testing for names but it doesn't fit the general case -- also checking against contents of models.py seems a bit error prone as well. And there seem to be nothing in actual fields' __dict__ or anywhere else.

Any clues?
解决方案
Well, South developers seemed to know it: model is autogenerated if
# Django 1.0/1.1
(not field.rel.through)
or
# Django 1.2+
getattr(getattr(field.rel.through, "_meta", None), "auto_created", False)
Woohoo!

                        
这篇关于如何在Django自动创建的ManyToMany通过模型和手动定义的模型之间进行调整？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！