PostgreSQL error code

PostgreSQL error 23505

23505 is the SQLSTATE PostgreSQL reports for unique violation, in class 23, Integrity Constraint Violation.

SQLSTATE	23505
Condition name	unique_violation
Class	23 — Integrity Constraint Violation

Reproduce it, then fix it

A product with id 1 already exists, and the primary key allows each id once. ON CONFLICT turns the insert into an update when the row is already there. Run the broken query to see the error, then switch to the fixed one. Edit either freely; every run is rolled back.

INSERT INTO products (id, name) VALUES (1, 'Webcam');

INSERT INTO products (id, name) VALUES (1, 'Webcam')
ON CONFLICT (id) DO UPDATE SET name = excluded.name
RETURNING id, name;

Source: PostgreSQL documentation, Appendix A