Reverse engineer an E-R schema from the following relational schema shown in SQL create table zipcodes (zip number (5), City varchar 2(30), primary key (zip)) create table employees (eno number(4) not null primary key, ename varchar2(30), zip number (5) references zip codes hdate date); create table parts (pno number (5) not null primary key, pname varchar2(30), qoh integer check (qoh) >= 0), price number (6, 2) check (price >= 0.0), olevel integer); create table customers (cno number (5) not null primary key, cname varchar2 (30), street varchar2(30), zip number (5) references zipcodes, phone char (12)) create table orders (ono number (5) not null primary key, cno number (5) references customers, eno number (4) references employees, received date shipped date); create table odetails(ono number (5) not null references orders, pno number (5) not null references parts, qty integer check (qty > 0), primary key (ono, pno))