Oracle / PLSQL: ORA-00001 Error Message

Learn the cause and how to resolve the ORA-00001 error message in Oracle.

Description

When you encounter an ORA-00001 error, the following error message will appear:

• ORA-00001: unique constraint (constraint_name) violated

Cause

You tried to execute an INSERT or UPDATE statement that has created a duplicate value in a field restricted by a unique index.

Resolution

The option(s) to resolve this Oracle error are:

Option #1

Drop the unique constraint.

Option #2

Change the constraint to allow duplicate values.

Option #3

Modify your SQL so that a duplicate value is not created.

Note

If you are not sure which unique constraint was violated, you can run the following SQL:

SELECT DISTINCT table_name
FROM all_indexes
WHERE index_name = 'CONSTRAINT_NAME';

In our example (see picture above), our constraint name would be SYS_C002459 and we would execute the following SQL:

SELECT DISTINCT table_name
FROM all_indexes
WHERE index_name = 'SYS_C002459';

This would return the name of the table whose unique constraint we violated.