High ORM Question 164 of 228

Why can bulk_create skip signals, and what else does it skip?

Python & Django · Speak this in 60–90 seconds · Faridabad & Delhi NCR

PICTURE THIS: DATABASE INDEX

Without indexScan every row

With indexJump to keys

CostWrites slower

Simple meaning

bulk_create issues INSERT in batches and does not call save() per row, so pre_save/post_save do not run.

WHY — ORM instead of guessing?

Why interviewers care about ORM:

They are checking judgment

on ORM.

A good answer names

the situation, the default choice, and one exception - that reads as experience.

Stay structured

Name the idea, why it exists, then one short example.

Close cleanly

End with when you use it and one common pitfall.

STEPS — What happens step by step?

Before you speak the answer, walk the interviewer through these steps:

1
bulk_create issues INSERT in
batches and does not call save() per row, so pre_save/post_save do not run.
2
Auto fields and some
database defaults may need ignore_conflicts or returning PKs depending on the backend.
3
If receivers must run,
loop with save() or emit signals yourself after the bulk insert.
4
Give an example
One tiny concrete case you can say aloud.
5
Common mistake
What juniors usually get wrong.
6
Close
When you pick this over the alternative.

EXAMPLE — See it in action

Here's a short line you can speak, broken into clear beats:

Say this line

“Auto fields and some database defaults may need ignore_conflicts or returning PK”

Break into beats

Autofieldsandsomedatabasedefaults

Speaking order

2987408337471632900

Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.

Key takeaway

bulk_create issues INSERT in batches and does not call save() per row, so pre_save/post_save do not run. Auto fields and some database defaults may need ignore_conflicts or returning PKs depending on the backend.