A$.$ Create department table:

CREATE TABLE departments $($ department$\_$id number$(10)$ not null, department$\_$name varchar$2(50)$ not null$)$

$1-$ Alter the department table by changing the department$\_$id to dept$\_$id$.$

$2-$ Alter the department table by changing the name of the table to depts.

B$.$ Create employees table:

CREATE TABLE employees $($ employee$\_$number number$(10)$ not null, employee$\_$name varchar$2(50)$ not null, department$\_$id number$(10)$;

$1-$ Alter employee table by adding two columns salary of type int, address of type varchar$(50)$;

C$.$ CREATE staff$\_$members TABLE:

CREATE TABLE staff$\_$members $($ employee$\_$number number$(10)$ not null, employee$\_$name varchar$2(50)$ not null, department$\_$id number$(10))$

$1-$ Alter table by changing the employee$\_$name column to varchar$2(75).$

D$.$ Create table customers:

CREATE TABLE customers $($ customer$\_$id number$(10)$ not null, customer$\_$name varchar$2(50),$ address varchar$2(50),$ city varchar$2(50),$ state varchar$2(25),$ zip$\_$code varchar$2(10))$

Drop zip$\_$code