mirror of https://github.com/apache/cassandra
93 lines
3.4 KiB
Plaintext
93 lines
3.4 KiB
Plaintext
Executive summary
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-----------------
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Cassandra is a 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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Requirements
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------------
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. Java >= 1.8 (OpenJDK and Oracle JVMS have been tested)
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. Python 2.7 (for cqlsh)
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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.
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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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****
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Note for Windows users: to install Cassandra as a service, download
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http://commons.apache.org/daemon/procrun.html[Procrun], set the
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PRUNSRV environment variable to the full path of prunsrv (e.g.,
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C:\procrun\prunsrv.exe), and run "bin\cassandra.bat install".
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Similarly, "uninstall" will remove the service.
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****
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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 2.2.0 | Cassandra 1.2.0 | CQL spec 3.0.0 | Thrift protocol 19.35.0]
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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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https://github.com/apache/cassandra/blob/trunk/doc/cql3/CQL.textile[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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* Getting started: http://wiki.apache.org/cassandra/GettingStarted
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* Join us in #cassandra on irc.freenode.net 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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* Planet Cassandra aggregates Cassandra articles and news:
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http://planetcassandra.org/
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