Django: Set foreign key using integer?
Solution 1:
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
Solution 2:
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)