| 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 3.4.7 | 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 |
| user-subscribe@cassandra.apache.org. |
| * Subscribe to the Developer mailing list by sending a mail to |
| dev-subscribe@cassandra.apache.org. |
| * 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. |
