Create a database schema, Database Management System

Consider a database schema consisting of four relations, whose schemas are:

Product (maker, model, type)

PC (model, speed, ram, hd, price)

Laptop (model, speed, ram, hd, screen, price)

Printer (model, color, type, price)

The Product relation gives the manufacturer, model number and type (PC, laptop, or printer) of various products. (We assume for convenience that model numbers are unique over all manufacturers and product types; note that in reality, we can include a code for the manufacturer and product type as part of the model number.) The PC relation gives for each model number that is a PC, the speed (of the processor in GHz), the amount of RAM (in megabytes), the size of the hard diskĀ  (in gigabytes), and the price. The Laptop relation is similar, except that the screen size (in inches) is also included. The Printer relation records for each printer model whether the printer produces color output (true or false), the process type (laser or ink-jet, typically), and the price.

Write the SQL CREATE TABLE (SQL DDL) statements for the above schema, specifying any primary key and unique constraints.

(Note that referential integrity ("foreign key") must ideally specify that the model in Product must appear in one of the PC, Laptop and Printer tables; we will learn how to specify such constraints later in the course using triggers; they cannot be specified using foreign key constraints - for this problem, you NEED NOT specify these constraints).

Include the SQL statements and appropriate screen shots showing that your CREATE TABLE statements succeeded into your submission document.

Posted Date: 3/20/2013 1:52:54 AM | Location : United States







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