[Django]-Django: Set foreign key using integer?

by

239👍

✅

Yep:

employee = Employee(first_name="Name", last_name="Name")
employee.type_id = 4
employee.save()

ForeignKey fields store their value in an attribute with _id at the end, which you can access directly to avoid visiting the database.

The _id version of a ForeignKey is a particularly useful aspect of Django, one that everyone should know and use from time to time when appropriate.

caveat: [ < Django 2.1 ]

@RuneKaagaard points out that employee.type is not accurate afterwards in recent Django versions, even after calling employee.save() (it holds its old value). Using it would of course defeat the purpose of the above optimisation, but I would prefer an accidental extra query to being incorrect. So be careful, only use this when you are finished working on your instance (eg employee).

Note: As @humcat points out below, the bug is fixed in Django 2.1

👤Will Hardy

56👍

An alternative that uses create to create the object and save it to the database in one line:

employee = Employee.objects.create(first_name='first', last_name='last', type_id=4)
👤Jacinda

1👍

Just to emphasize something on the accepted answer (based on my experience):
When you want to add a value in the "id" field of the foreign key (hope that this is clear), you must add "_id" at the end of the name defined by you in that class.

In this example:
employee = Employee(first_name="Name", last_name="Name", type_id=4)

Here "type" refers to "type" defined in the "Employee" class.

Note that if you have defined something like "foo_id", you still must add the "_id" suffix and the result will be "foo_id_id"

PS: I can’t comment or do other actions (not enough reputation points)

👤Alext

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