Cassandra data model pdf

Cassandra Data Model – Learn Cassandra in simple and easy steps starting from Introduction, Architecture And Data Model, Installation, Referenced Api, Cassandra Cqlsh, Shell Commands, Create Keyspace, Alter Keyspace, Drop Keyspace, Create Table, Alter Table, Drop Table, Truncate Table, Create Index, Drop Index, Create Data, Update Data, Delete Data, Batch, Select Clause, Cql Datatypes, Cql Collections, Cql User-Defined Datatypes. Cassandra, Introduction, Architecture Cassandra data model pdf Data Model, Installation, Referenced Api, Cassandra Cqlsh, Shell Commands, Create Keyspace, Alter Keyspace, Drop Keyspace, Create Table, Alter Table, Drop Table, Truncate Table, Create Index, Drop Index, Create Data, Update Data, Delete Data, Batch, Select Clause, Cql Datatypes, Cql Collections, Cql User-Defined Datatypes. The data model of Cassandra is significantly different from what we normally see in an RDBMS. This chapter provides an overview of how Cassandra stores its data.

Cassandra database is distributed over several machines that operate together. The outermost container is known as the Cluster. For failure handling, every node contains a replica, and in case of a failure, the replica takes charge. Cassandra arranges the nodes in a cluster, in a ring format, and assigns data to them. Keyspace is the outermost container for data in Cassandra. It is the number of machines in the cluster that will receive copies of the same data.

It is nothing but the strategy to place replicas in the ring. Keyspace is a container for a list of one or more column families. A column family, in turn, is a container of a collection of rows. Each row contains ordered columns. Column families represent the structure of your data. Each keyspace has at least one and often many column families. The following illustration shows a schematic view of a Keyspace.

A column family is a container for an ordered collection of rows. Each row, in turn, is an ordered collection of columns. The following table lists the points that differentiate a column family from a table of relational databases. A schema in a relational model is fixed.

Once we define certain columns for a table, while inserting data, in every row all the columns must be filled at least with a null value. In Cassandra, although the column families are defined, the columns are not. You can freely add any column to any column family at any time. Relational tables define only columns and the user fills in the table with values.