Oracle ALTER TABLE MODIFY Column :Modify the column’s visibility and Allow or not Allow NULL values
Oracle ALTER TABLE MODIFY Column
Summary: in this tutorial, you will learn how to use the Oracle ALTER TABLE MODIFY column statement to change the definition of existing columns.
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;
Code language: SQL (Structured Query Language) (sql)
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:
Modify the column’s visibility
Allow or not allow null values
Shorten or widen the size of the column
Change the default value of a column
Modify the expression of the virtual columns