Apache Cassandra 0.6 Documentation

Thinking in Terms of Queries

This document corresponds to an earlier product version. Make sure you are using the version that corresponds to your version.

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Unlike the fully-relational model, where data is normalized for storage in the database and then joined during queries, Cassandra is at its best when there is approximately one column family per expected type of query.

This means that data should typically be denormalized and structured in such a way that one or multiple rows in a single column family are used to answer each query. This sacrifices disk space (one of the cheapest resources for a server) in order to reduce the number of disk seeks and the amount of network traffic.