Cassandra Concepts: Difference between revisions
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SELECT "email" FROM "user_tweets" WHERE "username" = 'john'; | SELECT "email" FROM "user_tweets" WHERE "username" = 'john'; | ||
= | =Cluster= | ||
A cluster is a set of nodes (or <font color=darkgray>data centers</font>) deployed in a ring architecture. A cluster has a name, which will be used by participating nodes. | |||
=Node= | |||
=Keyspace= | =Keyspace= | ||
<span id='Schema'></span>The equivalent of a '''schema''' of relational database. The keyspace is the outermost container for data. A keyspace is characterized by its [[#Replication_Factor|replication factor]], [[#Replica_Placement_Strategy|replica placement strategy]] and its [[#Column_Family|column families]]. | |||
==Replication Factor== | |||
==Replica Placement Strategy== | |||
==Column Family== | |||
==Keyspace Operations== | ==Keyspace Operations== | ||
* [[Cassandra_Operations#Keyspace_Operations|List Keyspaces]] | * [[Cassandra_Operations#Keyspace_Operations|List Keyspaces]] | ||
* [[Cassandra_Operations#Keyspace_Operations|Describe a Keyspace]] | * [[Cassandra_Operations#Keyspace_Operations|Describe a Keyspace]] | ||
=Table= | =Table= | ||
Revision as of 20:54, 25 September 2019
Internal
Overview
Cassandra is NoSQL a key-value database. It provides continuous availability with no single point of failure. The database uses a ring design and consistent hashing. In a ring design there is no master node, all nodes are identical and communicate with each other as peers. This architecture allows it to scale horizontally, by incrementally adding nodes with no reconfiguration. Provides good performance for large amounts of data.
CQL
Cassandra Query Language
SELECT "email" FROM "user_tweets" WHERE "username" = 'john';
Cluster
A cluster is a set of nodes (or data centers) deployed in a ring architecture. A cluster has a name, which will be used by participating nodes.
Node
Keyspace
The equivalent of a schema of relational database. The keyspace is the outermost container for data. A keyspace is characterized by its replication factor, replica placement strategy and its column families.
Replication Factor
Replica Placement Strategy
Column Family
Keyspace Operations
Table
Row
Column
Partition Key
Has primary key, or lookup key semantics.