Data Modeling and Normalization

OVERVIEW

The task in this project is to design a normalized database that could be used to collect and store information for a video rental outlet. The database should be structured to support tasks such as:

• tracking rentals by title and by customer;
• producing reports, such as rentals due on a certain date;
• categorizing rentals by media type (e.g., Blu-Ray, DVD, Game).

The assignment does not require you to produce examples of the reports listed, but only that the database be correctly structured to allow the query and reporting features of a DBMS, such as Access, to work properly.

You will need to collect information about several titles in each category, which can be done online, at your local video store, or from your personal media collection. You will be given an initial, un-normalized field list of data items to be tracked, which you will normalize into the appropriate separate tables.

The database students will prepare in this project is somewhat simplified in comparison to a real-world application. For example, only brief customer address information is included, to reduce the amount of data input required for the project. We have also simplified the example in terms of structure; ignoring, for example, the complexities of a real-world video outlet, such as varying rental periods for different products.

The initial field list does not include all of the appropriate key fields for the tables that will be created, so suitable key fields should be added to the tables as required.

This project is most easily completed using MS-Access; for a detailed discussion of the other options for completing the Project, please see “Alternatives to Using MS Access” below.

PROJECT DETAILS

The following is a list of essential data items to be recorded. As noted above, additional fields may be required as keys for the tables you will create from these fields.

• date of rental
• due date
• media item title
• media item category
• category description
• category code
• customer ID#
• customer lastname
• customer firstname
• customer address
• customer phone#

If only a single table were made from all the fields listed above, the result would be a system in which every rental would have to include duplicate customer and media item details. In addition to wasting input time duplicating data, such a system would also be highly prone to error, as any change to customer data (a change of address, for example) would also result in different records showing different content for the same fields, unless every historical record for that customer was updated.

The relational database model was designed to solve those problems by identifying key data entities, separating them into their own tables, and relating the tables using foreign keys. (The foreign key is usually the primary key from one table, placed in one or more other tables to create linkages.)

This allows for customer details, for example, to be recorded once, in a table reserved for that purpose, and referenced in other tables by a unique identifier (key), such as Customer ID#.

Your task is to create a simple relational database from the field list above. The required tables are Customers, Media, Categories, and Rentals; each of which should be properly provided with a primary key, and each of which should be related to other tables as required.

All four database tables should be populated with records as follows:

• Customers—at least 10
• Categories—three records, one describing each of the media types: DVD, Blu-Ray, or Game
• Media—at least 30 records, representing a selection of DVD movies, Blu-Ray movies, and Games.
• Rentals—at least 20 records.