RDBMS vs Cassandra data models

The following table lists down the points that differentiate the data model of Cassandra from that of an RDBMS.

RDBMS Cassandra
RDBMS deals with structured data. Cassandra deals with unstructured data.
It has a fixed schema. Cassandra has a flexible schema.
In RDBMS, a table is an array of arrays. (ROW x COLUMN) In Cassandra, a table is a list of “nested key-value pairs”. (ROW x COLUMN key x COLUMN value)
Database is the outermost container that contains data corresponding to an application. Keyspace is the outermost container that contains data corresponding to an application.
Tables are the entities of a database. Tables or column families are the entity of a keyspace.
Row is an individual record in RDBMS. Row is a unit of replication in Cassandra.
Column represents the attributes of a relation. Column is a unit of storage in Cassandra.
RDBMS supports the concepts of foreign keys, joins. Relationships are represented using collections.

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