Oracle® Database 11g / 12c / 18c error codes ORA-01451: column to be modified to NULL cannot be modified to NULL

ORA-01451: column to be modified to NULL cannot be modified to NULL

Oracle Error Code: ORA-01451

Cause: the column may already allow NULL values, the NOT NULL constraint is part of a primary key or check constraint.

Action: if a primary key or check constraint is enforcing the NOT NULL constraint, then drop that constraint.