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https://github.com/apache/cassandra

Apache Cassandra®
https://github.com/apache/cassandra

cassandra database java

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Apache Cassandra®

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README 

        
Apache Cassandra

-----------------



Apache Cassandra is a highly-scalable partitioned row store. Rows are organized into tables with a required primary key.



https://cwiki.apache.org/confluence/display/CASSANDRA2/Partitioners[Partitioning] means that Cassandra can distribute your data across multiple machines in an application-transparent matter. Cassandra will automatically repartition as machines are added and removed from the cluster.



https://cwiki.apache.org/confluence/display/CASSANDRA2/DataModel[Row store] means that like relational databases, Cassandra organizes data by rows and columns. The Cassandra Query Language (CQL) is a close relative of SQL.



For more information, see http://cassandra.apache.org/[the Apache Cassandra web site].



Issues should be reported on https://issues.apache.org/jira/projects/CASSANDRA/issues/[The Cassandra Jira].



Requirements

------------

- Java: see supported versions in build.xml (search for property "java.supported").

- Python: for `cqlsh`, see `bin/cqlsh` (search for function "is_supported_version").



Getting started

---------------



This short guide will walk you through getting a basic one node cluster up

and running, and demonstrate some simple reads and writes. For a more-complete guide, please see the Apache Cassandra website's https://cassandra.apache.org/doc/latest/cassandra/getting_started/index.html[Getting Started Guide].



First, we'll unpack our archive:



  $ tar -zxvf apache-cassandra-$VERSION.tar.gz

  $ cd apache-cassandra-$VERSION



After that we start the server. Running the startup script with the -f argument will cause

Cassandra to remain in the foreground and log to standard out; it can be stopped with ctrl-C.



  $ bin/cassandra -f



Now let's try to read and write some data using the Cassandra Query Language:



  $ bin/cqlsh



The command line client is interactive so if everything worked you should

be sitting in front of a prompt:



----

Connected to Test Cluster at localhost:9160.

[cqlsh 6.3.0 | Cassandra 5.0-SNAPSHOT | CQL spec 3.4.8 | Native protocol v5]

Use HELP for help.

cqlsh>

----



As the banner says, you can use 'help;' or '?' to see what CQL has to

offer, and 'quit;' or 'exit;' when you've had enough fun. But lets try

something slightly more interesting:



----

cqlsh> CREATE KEYSPACE schema1

       WITH replication = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };

cqlsh> USE schema1;

cqlsh:Schema1> CREATE TABLE users (

                 user_id varchar PRIMARY KEY,

                 first varchar,

                 last varchar,

                 age int

               );

cqlsh:Schema1> INSERT INTO users (user_id, first, last, age)

               VALUES ('jsmith', 'John', 'Smith', 42);

cqlsh:Schema1> SELECT * FROM users;

 user_id | age | first | last

---------+-----+-------+-------

  jsmith |  42 |  john | smith

cqlsh:Schema1>

----



If your session looks similar to what's above, congrats, your single node

cluster is operational!



For more on what commands are supported by CQL, see

http://cassandra.apache.org/doc/latest/cql/[the CQL reference]. A

reasonable way to think of it is as, "SQL minus joins and subqueries, plus collections."



Wondering where to go from here?



  * Join us in #cassandra on the https://s.apache.org/slack-invite[ASF Slack] and ask questions.

  * Subscribe to the Users mailing list by sending a mail to

    [email protected].

  * Subscribe to the Developer mailing list by sending a mail to

    [email protected].

  * Visit the http://cassandra.apache.org/community/[community section] of the Cassandra website for more information on getting involved.

  * Visit the http://cassandra.apache.org/doc/latest/development/index.html[development section] of the Cassandra website for more information on how to contribute.