A more efficient way to extract IDs from Foreign Key fields

Given a Django foreign key field related_model, I previously used:

related_model_id = model_instance.related_model_id

and

related_model_id = model_instance.related_model.id

interchangeably.

I learnt that the latter results in an additional DB query for all of related_model’s fields versus the former. This is because related_model_id is just the name of the DB column Django creates to represent the foreign key, and is therefore available when model_instance is first loaded into memory.

• Python
• Django
• Database