Moderate ORM Question 104 of 228

How do you add a database index on a Django model?

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

Set db_index=True on a field, or declare indexes in Meta.indexes / unique_together / UniqueConstraint.

WHY — ORM instead of guessing?

Why interviewers care about ORM:

This is a process

question about ORM.

Panels listen for order,

trade-offs, and what you would actually do on a Python project - not buzzwords.

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
Set db_index=True on a
field, or declare indexes in Meta.indexes / unique_together / UniqueConstraint.
2
Indexes speed filters and
joins but slow writes, so index columns you actually query.
3
After changing Meta, generate
a migration.
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

“Indexes speed filters and joins but slow writes, so index columns you actually q”

Break into beats

Indexesspeedfiltersandjoinsbut

Speaking order

2987408337471632900

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

Key takeaway

Set db_index=True on a field, or declare indexes in Meta.indexes / unique_together / UniqueConstraint. Indexes speed filters and joins but slow writes, so index columns you actually query.