The Cassandra data model

From Version 1.2 onwards, Cassandra has CQL as its primary way to access and alter the database. CQL is an abstraction layer that makes you feel like you are working with RDBMS, but the underlying data model does not support all the features that a traditional database or SQL provides. There is no group by, no relational integrity, foreign key constraints, and no join. There is some support for order, distinct, and triggers. There are things such as time to live (TTL) and write time functions. So Cassandra, like most of the NoSQL databases, is generally less featured compared to the number of features traditional databases provide.

Cassandra is designed for extremely high-read and high-write speed and horizontal scalability. Without some of the analytical features of traditional systems, developers need to work around Cassandra's shortcomings by planning ahead. In the Cassandra community, it is generally referred to as modeling the database based on what queries...