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 Modify the column's visibility;Here, table_name – It is the name of table in which we want to make changes column_name – It is the name of column whose definition we want to change modification – It is the action or change that we want in the existing the structure Some of the modifications that we can perform are as follows Allow or Disallow NULL values in column;Oct 30, 14 · In Oracle, if we add a column to a table which is NOT NULL, we are allowed to do it directly, in a single statement, as long as we supply a DEFAULT value to populate any preexisting rows This would mean that every row in the table was updated with the default value Sql With Oracle 10g Xe Using Alter Table To Modify Table Columns Youtube Alter table modify column oracle remove not null