Finally, you should know that it is possible to "alter"
a table after it has been created using wither a standard GUI tool or
by using the ALTER SQL command as follows:
ALTER TABLE TABLE_NAME
DROP COLUMN_NAME, COLUMN_NAME
ADD COLUMN_NAME DATA_TYPE, COLUMN_NAME DATA_TYPE
RENAME COLUMN_NAME NEW NAME
MODIFY COLUMN_NAME DATA_TYPE;
such as the following case in which
we alter the table named EMPLOYEES by dropping the E_GENDER
Column and adding an E_ZIP column which will accept INTEGERS
and which must be filled in for every new employee added to the table,
and the E_MIDDLE_INIT column which will accept a single
character as a value.
ALTER TABLE EMPLOYEES
DROP E_GENDER
ADD E_ZIP INTEGER NOT NULL,
E_MIDDLE_INIT CHAR (1);
