Column

ORA-12991: column is referenced in a multi-column constraint

by Ed Chen
April 25, 2020May 6, 2020

ORA-12991 ORA-12991 means that the column you want to drop is bound to some multi-column constraint. Usually, it's a primary key constraint, but not always.… Read More »

How to Resolve ORA-01442: column to be modified to NOT NULL is already NOT NULL

by Ed Chen
December 25, 2019December 26, 2019

ORA-01442 ORA-01442 means that the target column is already NOT NULL, you don't have to add it again by modifying the column. I know sometimes… Read More »

How to Add or Drop NOT NULL Constraint

by Ed Chen
November 23, 2019January 8, 2020

Add NOT NULL Constraint As I mentioned in How to Resolve ORA-00904 for ALTER TABLE ADD CONSTRAINT, NOT NULL is a constraint, but it's more… Read More »

How to Resolve ORA-12899: value too large for column

by Ed Chen
November 13, 2019November 13, 2019

ORA-12899 ORA-12899 means that the value of being inserted or updated data is larger than column's allowable length that is defined in the table. Let's… Read More »