ALTER TABLE MODIFY

How to Modify VARCHAR2 to CLOB of a Column

by Ed Chen
February 24, 2021December 8, 2022
2 Comments

Data Type Conversion 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-22858: invalid alteration of datatype

by Ed Chen
February 23, 2021May 19, 2022

ORA-22858 When we tried to convert VARCHAR2 to CLOB, we got ORA-22858. SQL> alter table hr.locations modify (city clob); alter table hr.locations modify (city clob)… Read More »

How Oracle Disable NOT NULL Constraint

by Ed Chen
November 23, 2019December 10, 2022

After you add a NOT NULL constraint to a column, you might want it stop temporarily. In such moment, you should consider to disable NOT… Read More »

How Oracle Add NOT NULL Constraint

by Ed Chen
November 23, 2019December 10, 2022

Add NOT NULL Constraint As I mentioned in resolving ORA-00904 for adding a constraint, NOT NULL is a constraint, but it's more like an attribute… Read More »