mirror of https://github.com/apache/cassandra
89 lines
3.7 KiB
Plaintext
89 lines
3.7 KiB
Plaintext
Apache Cassandra
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Apache Cassandra is a highly-scalable partitioned row store. Rows are organized into tables with a required primary key.
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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.
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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.
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For more information, see http://cassandra.apache.org/[the Apache Cassandra web site].
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Issues should be reported on https://issues.apache.org/jira/projects/CASSANDRA/issues/[The Cassandra Jira].
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Requirements
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------------
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- Java: see supported versions in build.xml (search for property "java.supported").
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- Python: for `cqlsh`, see `bin/cqlsh` (search for function "is_supported_version").
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Getting started
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---------------
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This short guide will walk you through getting a basic one node cluster up
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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].
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First, we'll unpack our archive:
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$ tar -zxvf apache-cassandra-$VERSION.tar.gz
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$ cd apache-cassandra-$VERSION
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After that we start the server. Running the startup script with the -f argument will cause
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Cassandra to remain in the foreground and log to standard out; it can be stopped with ctrl-C.
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$ bin/cassandra -f
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Now let's try to read and write some data using the Cassandra Query Language:
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$ bin/cqlsh
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The command line client is interactive so if everything worked you should
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be sitting in front of a prompt:
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----
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Connected to Test Cluster at localhost:9160.
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[cqlsh 6.3.0 | Cassandra 5.0-SNAPSHOT | CQL spec 3.4.8 | Native protocol v5]
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Use HELP for help.
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cqlsh>
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----
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As the banner says, you can use 'help;' or '?' to see what CQL has to
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offer, and 'quit;' or 'exit;' when you've had enough fun. But lets try
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something slightly more interesting:
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----
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cqlsh> CREATE KEYSPACE schema1
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WITH replication = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };
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cqlsh> USE schema1;
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cqlsh:Schema1> CREATE TABLE users (
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user_id varchar PRIMARY KEY,
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first varchar,
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last varchar,
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age int
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);
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cqlsh:Schema1> INSERT INTO users (user_id, first, last, age)
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VALUES ('jsmith', 'John', 'Smith', 42);
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cqlsh:Schema1> SELECT * FROM users;
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user_id | age | first | last
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---------+-----+-------+-------
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jsmith | 42 | john | smith
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cqlsh:Schema1>
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----
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If your session looks similar to what's above, congrats, your single node
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cluster is operational!
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For more on what commands are supported by CQL, see
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http://cassandra.apache.org/doc/latest/cql/[the CQL reference]. A
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reasonable way to think of it is as, "SQL minus joins and subqueries, plus collections."
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Wondering where to go from here?
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* Join us in #cassandra on the https://s.apache.org/slack-invite[ASF Slack] and ask questions.
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* Subscribe to the Users mailing list by sending a mail to
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user-subscribe@cassandra.apache.org.
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* Subscribe to the Developer mailing list by sending a mail to
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dev-subscribe@cassandra.apache.org.
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* Visit the http://cassandra.apache.org/community/[community section] of the Cassandra website for more information on getting involved.
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* Visit the http://cassandra.apache.org/doc/latest/development/index.html[development section] of the Cassandra website for more information on how to contribute.
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