Cassandra is a high performance and highly scalable distributed NoSQL database management system. RDBMS is a Database management system or software which is designed for relational databases.

Cassandra is a NoSQL database. RDBMS uses SQL for querying and maintaining the database.

Cassandra deals with unstructured data. RDBMS deals with structured data.

Cassandra has a flexible schema. RDBMS has fixed schema.

Cassandra has peer-to-peer architecture with no single point of failure. RDBMS has master-slave core architecture means a single point of failure.

Cassandra handles high volume incoming data velocity. RDBMS handles moderate incoming data velocity.

In Cassandra there are various data source means data come from one/few location. In RDBMS there is limited data source means data come from many locations.

Cassandra supports simple transactions. RDBMS supports complex and nested transactions.

In Cassandra the outermost container is Keyspace. In RDBMS the outermost container is database.

Cassandra follows decentralized deployments. RDBMS follows centralized deployments.

In Cassandra data written in many locations. In RDBMS mainly data are written in one location.

In Cassandra row represents a unit of replication. In RDBMS row represents a single record.

In Cassandra column represents a unit of storage. In RDBMS column represents an attribute.

In Cassandra, relationships are represented using collections. In RDBMS relationships are represented using keys and join etc.