/ 
DBD-Cassandra-0.11
River stage zero No dependents
/ DBD::Cassandra

NAME

DBD::Cassandra - Database driver for Cassandra's CQL3

EXAMPLE

use DBI;

my $dbh = DBI->connect("dbi:Cassandra:host=localhost;keyspace=test", $user, $password, { RaiseError => 1 });
my $rows = $dbh->selectall_arrayref("SELECT id, field_one, field_two FROM some_table");

for my $row (@$rows) {
    # Do something with your row
}

$dbh->do("INSERT INTO some_table (id, field_one, field_two) VALUES (?, ?, ?)",
    { Consistency => "quorum", Retries => 1 },
    1, "String value", 38962986
);

$dbh->disconnect;

DESCRIPTION

DBD::Cassandra is a Perl5 Database Interface driver for Cassandra, using the CQL3 query language.

Class Methods

connect
use DBI;

$dsn = "dbi:Cassandra:database=$database";
$dsn = "dbi:Cassandra:keyspace=$keyspace;host=$hostname;port=$port";
$dsn = "dbi:Cassandra:keyspace=$keyspace;consistency=local_quorum";
keyspace
database
db

Optionally, a keyspace to use by default. If this is not specified, all queries must include the keyspace name.

hostname

Hostname to connect to. Defaults to localhost

port

Port number to connect to. Defaults to 9042

compression

The compression method we should use for the connection. Currently Cassandra allows lz4 and snappy. Defaults to the algorithm with the best compression ratio, if the server supports it. Compression can be disabled by setting compression=none.

Only used for data frames longer than 512 bytes, smaller frames get sent uncompressed.

cql_version

There are several versions of the CQL language and this option lets you pick one. Defaults to the highest available version. Consult your Cassandra manual to see which versions your database supports.

consistency

CONSISTENCY LEVELS

$dbh->do("INSERT INTO some_table (id, field_name) VALUES (?, ?)",
    { Consistency => "quorum" },
    @values
);

DBD::Cassandra accepts a Consistency attribute for statements. Supported consistency levels are any, one, two, three, quorum, all, local_quorum, each_quorum, serial, local_serial and local_one.

This attribute is ignored on statements that do not support it, such as CREATE.

A global consistency level can be defined as part of the DSN.

CAVEATS, BUGS, TODO

  • There is currently no support for transactions. begin_work will die if you try to use it.

  • Thread support is untested. Use at your own risk.

  • There is currently no support for asynchronous queries, and there are no plans to implement it. If you need to run a lot of queries in parallel, consider using fork to manage the parallel work.

  • Not all Cassandra data types are supported. These are currently supported:

    • ascii

    • bigint

    • blob

    • boolean

    • custom

    • double

    • float

    • int

    • text

    • timestamp

    • varchar

  • Cassandra/CQL3 is strict about the queries you write. When switching from other databases, such as MySQL, this may come as a surprise. This module supports quote(..), but try to use prepared statements instead. They will save you a lot of trouble.

LICENSE

This module is released under the same license as Perl itself.

AUTHORS

Tom van der Woerdt, tvdw@cpan.org