To change the definition of a column in a table, you use the ALTER TABLE MODIFY column syntax as follows:
ALTER TABLE table_name MODIFY column_name action;
The statement is straightforward. To modify a column of a table, you need to specify the column name, table name, and action that you want to perform.
Oracle allows you to perform many actions but the following are the main ones:
To modify multiple columns, you use the following syntax:
ALTER TABLE table_name MODIFY ( column_name_1 action, column_name_2 action, ... );