NOT NULL

How to Resolve ORA-01440: column to be modified must be empty to decrease precision or scale

by Ed Chen
March 13, 2021April 11, 2021

ORA-01440 ORA-01440 means that you can't decrease the number precision of the column values directly by modifying the definition of the column. Let's see a… Read More »

How to Modify VARCHAR2 to CLOB of a Column

by Ed Chen
February 24, 2021March 14, 2021

Major Data Types There're several major data types built in Oracle. Character Numeric Datetime LONG RAW LOB (Large Object) In each major data types, minor… Read More »

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

by Ed Chen
December 25, 2019March 23, 2021

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 Resolve ORA-01400: cannot insert NULL into

by Ed Chen
November 27, 2019January 17, 2020

ORA-01400 ORA-01400 means that there's a column which was found as NOT NULL is not listed in the INSERT statement, you have to provide a… Read More »

How to Add or Drop NOT NULL Constraint

by Ed Chen
November 23, 2019January 20, 2021

A. 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… Read More »

ORA-00904 Invalid Identifier - Oracle Database Object Name Recognition Examples

How to Resolve ORA-00904 Invalid Identifier

by Ed Chen
March 12, 2019January 20, 2021

ORA-00904 ORA-00904 means that you used an invalid identifier which is mostly an unmatched column name or used an incorrect or unqualified syntax in your… Read More »