PostgreSQL error code

PostgreSQL error 42830

42830 is the SQLSTATE PostgreSQL reports for invalid foreign key, in class 42, Syntax Error or Access Rule Violation.

SQLSTATE	42830
Condition name	invalid_foreign_key
Class	42 — Syntax Error or Access Rule Violation

Reproduce it, then fix it

A foreign key has to reference a primary key or unique column, and products.name is neither. Reference the product’s id. Run the broken query to see the error, then switch to the fixed one. Edit either freely; every run is rolled back.

CREATE TABLE reviews (
  id int PRIMARY KEY,
  product_name varchar(255) REFERENCES products (name)
);

CREATE TABLE reviews (
  id int PRIMARY KEY,
  product_id int REFERENCES products (id)
);
SELECT * FROM reviews;

Source: PostgreSQL documentation, Appendix A