Learning Apache Cassandra - Second Edition

Logical data model (query-driven design)

Our choice to store two representations of a single follow relationship is a prime example of query-driven design: the practice of designing table schemas to accommodate the data access patterns of our application rather than simply building structures to naturally represent the underlying data. In the case of follow relationships, either the user_outbound_follows or user_inbound_follows table is sufficient on its own to store the data about follow relationships; were we using a relational database, it is likely that we would only use one of these tables, with secondary indexes on the non-key columns for efficient lookup. But when using Cassandra, neither table is able to satisfy all of the query needs ...