A well-designed data model is central to availability in Cassandra, while a poorly chosen model can substantially handicap your application's resiliency. This idea may seem counterintuitive to those with backgrounds in relational database systems, but this chapter may very well be the most critical one in this book.

It's not that data models are unimportant in relational systems, but they are especially critical when attempting to maintain availability in a large distributed database. In fact, this topic is probably the least understood and most difficult aspect of transitioning to Cassandra.

The data modeling problem is somewhat exacerbated by a familiar SQL-style syntax that can lure unsuspecting users into believing they already understand the necessary principles. In reality, the similarity between CQL and SQL ends with syntax. The underlying data structure is vastly different, and therefore a new approach to designing your data model is required...