CODEWITHSUNDEEP
djangomany-to-many
user585936
user585936

Reputation:

How to query the implicit through table in django (ManyToMany field)?

In the django documentation it reads the following:

If you don’t specify an explicit through model, there is still an implicit through model class you can use to directly access the table created to hold the association.

However, I can not find out how I can access this table. Say I have this structure:

class Person(models.Model):
    name = models.CharField(max_length=50)

class Group(models.Model):
    name = models.CharField(max_length=128)
    members = models.ManyToManyField(Person)

And I would like to query the table that holds the person_groups (the implicit through table)... how do I do this?

PersonGroup.objects.all()

That does not work, and I can't find what syntax I should be using.

Upvotes: 8

Views: 2436

Answers (2)

cepbuch
cepbuch

Reputation: 516

In your case it'll be like Group.members.through.objects.all()

I.e. Group.members.through returns a model class like <class 'appname.models.Group_person'>

But I am still not sure that this will make your query more effective. You always can filter on one table, then filter its members or persons.

Upvotes: 10

HenryM
HenryM

Reputation: 5793

You'll need to define the explicit through table if you want to access it through the ORM.

Given the way you've defined the relationship you have 

person = Person.objects.get(id=x) 
groups = person.members_set.all()

and 

groups = Group.objects.get(id=x)
members = group.members

Otherwise you'll need to access the table through Raw SQL query

Upvotes: 1

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