Alter Table Examples

Example 1

Alter Table contracts Add approve varchar2(3);

Example 2

Alter Table contracts Drop column approve;


Example 3

Alter Table customers Set unused (first_name, last_name);

Example 4

Alter Table customers
    add CONSTRAINT fk_user
      FOREIGN KEY (user_id, user_name)
      REFERENCES user(user_id, user_name)
      ON DELETE CASCADE;