schema-foreign-key-indexes

Postgres does not automatically index foreign key columns. Missing indexes cause slow JOINs and CASCADE operations.

Skills
Databases
0

What it does and how to use it

A skill that teaches Claude Code to do databases tasks well. It is packaged knowledge the model uses whenever it is relevant.

Install the skill (command above).
In Claude Code, describe what you need - the skill turns on by itself when the context fits.
No commands to memorize: you talk in plain language and the skill does the rest.

Install (Claude Code)

mkdir -p .claude/skills/schema-foreign-key-indexes && curl -fsSL https://doutorai.pt/data/lib/skills__schema-foreign-key-indexes.md -o .claude/skills/schema-foreign-key-indexes/SKILL.md

Paste this command into the terminal, in your project folder, and the component installs automatically.

Content

---
title: Index Foreign Key Columns
impact: HIGH
impactDescription: 10-100x faster JOINs and CASCADE operations
tags: foreign-key, indexes, joins, schema
---

## Index Foreign Key Columns

Postgres does not automatically index foreign key columns. Missing indexes cause slow JOINs and CASCADE operations.

**Incorrect (unindexed foreign key):**

```sql
create table orders (
  id bigint generated always as identity primary key,
  customer_id bigint references customers(id) on delete cascade,
  total numeric(10,2)
);

-- No index on customer_id!
-- JOINs and ON DELETE CASCADE both require full ta

- 🔒 Full content on the Pro plan (€7.99/month) -

Need help with Claude Code?

Ask Dr AI - it explains things simply.

Need a tailor-made solution?

Not sure where to start with AI in your business? Get a free assessment and a tailored plan - no commitment.

Save hours every week with AI, no hassle

Doutor AI gives you 1,859 ready-to-copy AI prompts, by industry and in plain English - plus a complete technical library for those who want to go further.

See plans