ORA-00001: Unique Constraint Violated in Oracle – Complete Fix Guide (Step-by-Step) The ORA-00001: unique constraint violated error is one of the most common issues faced by Oracle Database developers and DBAs. It occurs when an attempt is made to insert or update data that already exists in a column defined with a UNIQUE or PRIMARY KEY constraint. If you're dealing with this error, don’t worry—this guide will help you identify, troubleshoot, and permanently fix ORA-00001 using real-world solutions. What is ORA-00001 Error? The ORA-00001 error occurs when a duplicate value violates a uniqueness rule enforced by Oracle. In simple terms: You tried to insert a value that already exists Oracle blocked it to maintain data integrity Error Message ORA-00001: unique constraint (SCHEMA.CONSTRAINT_NAME) violated The message often includes the constraint name , which is your first clue to solving the problem. Quick Fix (Fast Solution) If you're in a hurry, follow this: ...