I have two models A and B with an intermediary model C for holding a many-to-many relation using the through. as extra fields in C can have different values for the two same related objects of A and B, is it logically OK to do that? i.e. pair of foreign keys to (A, B) in C to be not unique (Django do not create unique_together on them)
我有两个模型A和B，中间模型C用于通过直通保持多对多关系。因为C中的额外字段对于A和B的两个相同的相关对象可以具有不同的值，所以在逻辑上可以这样做吗？即C中（A，B）的外键对不是唯一的（Django不会在它们上创建unique_together）
1 个解决方案
#1
1
It is possible for multiple relationships between two objects to exist in your through table. This can have surprising results when fetching related items, however, as a.b_set.all() will contain multiple copies of the item from B where there are multiple relationships. If this is not desired, then you can use a.b_set.all().distinct() to remove the duplicate items.
两个对象之间的多个关系可能存在于直通表中。但是，当获取相关项时，这会产生令人惊讶的结果，因为a.b_set.all（）将包含来自B的项目的多个副本，其中存在多个关系。如果不需要，则可以使用a.b_set.all（）。distinct（）删除重复项。
#1
1
It is possible for multiple relationships between two objects to exist in your through table. This can have surprising results when fetching related items, however, as a.b_set.all() will contain multiple copies of the item from B where there are multiple relationships. If this is not desired, then you can use a.b_set.all().distinct() to remove the duplicate items.
两个对象之间的多个关系可能存在于直通表中。但是，当获取相关项时，这会产生令人惊讶的结果，因为a.b_set.all（）将包含来自B的项目的多个副本，其中存在多个关系。如果不需要，则可以使用a.b_set.all（）。distinct（）删除重复项。