Verified Developer Solution • 100% Offline

Fix "duplicate key value violates unique constraint"

Solve database insert failures caused by colliding primary keys or reused UUIDs.

The Problem (Error Root Cause)Exception

Your database INSERT fails with `duplicate key value violates unique constraint`. You are trying to insert a row using an ID or column value that already exists in the table.

Identified via runtime validation & stack traces

The Solution (Step-by-Step Fix)Verified

If you are using sequential IDs, ensure your sequence is updated. If you are generating IDs client-side, use cryptographically secure UUIDv4 to guarantee global uniqueness without collisions.

Deterministic, non-destructive resolution

Code Standard: Bad Pattern vs Verified Fix

Live Syntax

Anti-Pattern vs Verified Fix

1-- ❌ Bad: Hardcoded or repeating ID
2INSERT INTO users (id) VALUES (1);
3 
4-- ✅ Good: Using UUIDv4
5INSERT INTO users (id) VALUES ('550e8400-e29b-41d4-a716-446655440000');

Test and resolve this using UUID / ULID / NanoID Generator

Execute directly in your browser memory. Zero API keys, zero network tracking, completely client-side.

Launch UUID / ULID / NanoID Generator

Frequently Asked Questions

Q:Can UUIDv4 collide?

The probability of a collision is practically zero. You would need to generate 1 billion UUIDs per second for 85 years to reach a 50% chance of collision.

Q:How do I generate thousands of UUIDs?

Use our UUID / ULID Generator to create bulk IDs instantly.