Abstraction Hierarchy:

The DDL statements for construction of the warehouse database:

database warehouse.

base description (A16).
type product kind (A8) = description.

base color (A10).
base stock (I8).
base price (R4,2).
type product (I7) = description, color, stock, price, product kind.

base company name (A20).
base address (A20).
base zip (A6).
base city (A16).
type supplier (A8) = company name, address, zip, city.

type purchased product (A9) = supplier, product, price.

base quantity (I3).
base date (D).
type delivery (A10) = purchased product, quantity, date.

base department name (A15).
base floor (I1).
base phone (I14).
base name (A20).
type department (A8) = department name, floor, phone, manager_name.

base initials (A5).
base job title (A5).
type employee (A4) = name, initials, address, zip, city, department, job title.

type saleable product (A10) = product, department.

base debt (R4,2).
type customer (A5) = name, initials, address, zip, city, debt.

base prepaid (R4,2).
type sale (A7) = sold product, quantity, price, customer, date, prepaid.

end.