23503 — Foreign Key Violation

Was verursacht diesen Fehler

The referenced row does not exist in the parent table, or a parent row is being deleted while child rows still reference it.

So beheben Sie ihn

Ensure the referenced record exists before inserting. Use ON DELETE CASCADE or SET NULL. Insert parent records before child records.

-- foreign_key_violation
INSERT INTO orders (user_id) VALUES (99999);
-- user_id 99999 does not exist in users table