Think About How Your Local Video Rental Store Works There

Think About How Your Local Video Rental Store Works There Are Many Cu

Think about how your local video rental store works. There are many customers renting many videos, and many videos sit on the shelves unrented. Customers can rent many videos at one time. Some videos are so popular that the video rental store keeps many copies. Create a document that shows the various business rules that define how a video rental store works with respect to entity classes and their relationships.

Now, draw the initial E-R diagram based on the rules you defined. Don’t worry about going through the normalization process at this point. Identify the appropriate relationships among the entity classes and define the minimum and maximum cardinality of each relationship.

---

Paper For Above instruction

Introduction

A video rental store operates as a dynamic environment where customers interact with a wide range of videos. Understanding the business rules that underpin this environment is essential for designing an effective Entity-Relationship (E-R) diagram. This paper discusses the core entities, their attributes, and the relationships among them, providing a comprehensive overview of the fundamental database structure necessary for managing a video rental store.

Core Entities and Business Rules

The primary entities in a video rental store are Customers, Videos, Copies, and Rentals. To analyze the relationships, it is crucial to understand the rules that dictate how these entities interact.

Customers

Customers are individuals who rent videos from the store. Each customer has attributes such as Customer ID, Name, Address, Phone Number, and Email. Customers can rent multiple videos simultaneously, and their rental history is stored for record-keeping and billing purposes.

Videos

Videos describe the movies or shows available for rent. Attributes for videos include Video ID, Title, Genre, Release Year, and Director. Some video titles are especially popular and have multiple copies in the store, which is managed through the Copies entity.

Copies

Copies represent individual physical units of a video. Each copy has a unique Copy ID and is associated with one Video. The number of copies for each video can vary, especially for popular titles, ensuring availability for multiple customers concurrently.

Rentals

Rentals record the transaction when a customer rents one or more copies of videos. Attributes include Rental ID, Customer ID, Copy ID, Rental Date, Due Date, and Return Date. A rental can involve multiple copies, and the relationship keeps track of which customer rented which copies and when.

Entity Relationships and Cardinalities

Understanding the cardinalities between entities is critical for the E-R diagram.

Customer to Rental

A customer can have zero, one, or many rentals at different times (minimum 0, maximum many). Each rental is associated with exactly one customer (minimum 1), making this a one-to-many (1:N) relationship.

Video to Copies

Each video can have zero or multiple copies (minimum 0, maximum many). Each copy belongs to exactly one video. This is a one-to-many (1:N) relationship from Video to Copies.

Copy to Rental

A single copy can be rented zero or once at a time (minimum 0, maximum 1), considering a copy cannot be rented to two customers simultaneously. Each rental involves one copy, making this a one-to-one (1:1) relationship during the rental period, but considering ongoing rentals, it’s modeled as a one-to-many from Copy to Rentals.

Rental to Copy

A rental can involve multiple copies, and each copy can be involved in many rentals over time. However, during a specific rental transaction, a copy is associated with exactly one rental. The relationship is many-to-many between Rentals and Copies, often resolved with an associative entity (Rental_Details).

Initial E-R Diagram Sketch

Based on the rules, the initial E-R diagram would include:

- Customers (CustomerID, Name, ContactInfo)

- Videos (VideoID, Title, Genre, Year, Director)

- Copies (CopyID, VideoID)

- Rentals (RentalID, CustomerID, RentalDate, DueDate, ReturnDate)

- Rental_Details (RentalID, CopyID)

Relationships:

- Customer to Rentals (1:N)

- Video to Copies (1:N)

- Copies to Rental_Details (1:N)

- Rentals to Rental_Details (1:N)

Cardinalities:

- Customer (1) ---- (0..N) Rent

- Video (1) ---- (0..N) Copies

- Copy (1) ---- (0..1) Rent (at a time)

- Rental (1) ---- (N) Copies (through Rental_Details)

Conclusion

The business rules governing a video rental store help establish a clear structure for the underlying database. The relationships among customers, videos, copies, and rentals support the operational needs such as tracking rentals, managing inventory, and ensuring customers have access to multiple copies of popular titles. The initial E-R diagram provides a foundation for further normalization and database implementation, ensuring efficiency and consistency in data management.

References

• Elmasri, R., & Navathe, S. B. (2015). Fundamentals of Database Systems (7th ed.). Pearson.
• Coronel, C., & Morris, S. (2015). Database Systems: Design, Implementation, & Management (11th ed.). Cengage Learning.