Hi Gagaro,

Upon further investigation it looks like the following thing is happening, 
you find have a similar example in the documentation 
<https://docs.djangoproject.com/en/1.8/topics/db/models/#extra-fields-on-many-to-many-relationships>
.

When you define an explicit through model Django generates a query name to 
allow direct reference to the intermediate relationship.

This query name is not customizable and is generated by lower casing the 
intermediate model name ('wishlist' in your case and 'membership' in the 
linked one).

The clash you're getting here is between this implicit query name and your 
User.wishlist field and would manifest itself if your were to call 
User.objects.filter(wishlist__...) where Django couldn't differentiate the 
field from the *through query name*.

I guess the clash message could be more clear when a clash happens with 
this implicit query name.

Simon

Le vendredi 23 octobre 2015 10:27:26 UTC-4, Gagaro a écrit :
>
> Hi Simon, thanks for the answer, it cleared some things up.
>
> However, I still have a question. The reverse relation is *wishlist_set* 
> by default. Why is Django bothered if the attribute is name *wishlist* (I 
> would understand if I named my attribute *wishlist_set*)?
>
> On Friday, 23 October 2015 15:40:42 UTC+2, Simon Charette wrote:
>>
>> Hi Gagaro,
>>
>> Intermediate models are just like other in this regard, they create a 
>> related relation hence the reported clash.
>>
>> You should either add related_name='+' on your Wishlist related fields or 
>> give them a unique name.
>>
>> Simon
>>
>> Le vendredi 23 octobre 2015 06:01:30 UTC-4, Gagaro a écrit :
>>>
>>> Hello,
>>>
>>> I have a situation I don't really understand. I have the following 
>>> models:
>>>
>>> class Wishlist(models.Model):
>>>     wine = models.ForeignKey('Wine')
>>>     user = models.ForeignKey('User')
>>>
>>>
>>> class Wine(models.Model):
>>>     name = models.CharField(max_length=32)
>>>
>>>
>>> class User(models.Model):
>>>     name = models.CharField(max_length=32)
>>>     wishlist = models.ManyToManyField(Wine, through=Wishlist)
>>>
>>> And the following error:
>>>
>>> models_test.Wishlist.user: (fields.E303) Reverse query name for 
>>>> 'Wishlist.user' clashes with field name 'User.wishlist'.
>>>> HINT: Rename field 'User.wishlist', or add/change a related_name 
>>>> argument to the definition for field 'Wishlist.user'.
>>>
>>>
>>> Is that an intended behaviors? In my understanding, there is no related 
>>> relation created for through models (IE: we can't directly get the Wishlist 
>>> instance from the User one). Why would the names clash in this case? And 
>>> why does it clashes on *wishlist*, the reverse relation shouldn't be 
>>> *wishlist_set* and not *wishlist*?
>>>
>>> Thanks.
>>>
>>

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