All errors › ORA errors
ORA-01452: Cannot CREATE UNIQUE INDEX; duplicate keys found
What it means
Existing data violates the uniqueness you want to enforce.
How to fix it
Find duplicates with GROUP BY ... HAVING COUNT(*) > 1 and clean them, or use EXCEPTIONS INTO with a constraint.
Catch it before it runs
ORA Error Helper
Explains ORA-/PLS- codes inside JetBrains IDEs and DataGrip. PL/SQL Lint
Flags risky PL/SQL patterns while you type. Oracle Plan Reader
Reads execution plans and points at the slow step. PL/SQL in Practice
Kindle book with practical PL/SQL for working developers.
Explains ORA-/PLS- codes inside JetBrains IDEs and DataGrip. PL/SQL Lint
Flags risky PL/SQL patterns while you type. Oracle Plan Reader
Reads execution plans and points at the slow step. PL/SQL in Practice
Kindle book with practical PL/SQL for working developers.
Nearby errors
Updated 2026-11-12.