Cassandra: The Definitive Guide, 2nd Edition

Chapter 5. Data Modeling

In this chapter, you’ll learn how to design data models for Cassandra, including a data modeling process and notation. To apply this knowledge, we’ll design the data model for a sample application, which we’ll build over the next several chapters. This will help show how all the parts fit together. Along the way, we’ll use a tool to help us manage our CQL scripts.

Conceptual Data Modeling

First, let’s create a simple domain model that is easy to understand in the relational world, and then see how we might map it from a relational to a distributed hashtable model in Cassandra.

To create the example, we want to use something that is complex enough to show the various data structures and design patterns, but not something that will bog you down with details. Also, a domain that’s familiar to everyone will allow you to concentrate on how to work with Cassandra, not on what the application domain is all about.

For our example, we’ll use a domain that is easily understood and that everyone can relate to: making hotel reservations.

Our conceptual domain includes hotels, guests that stay in the hotels, a collection of rooms for each hotel, the rates and availability of those rooms, and a record of reservations booked for guests. Hotels typically also maintain a collection of “points of interest,” which are parks, museums, shopping galleries, monuments, or other places near the hotel that guests might want to visit during their stay. Both hotels and points of ...