NAME

MongoDB::Database - A MongoDB Database

VERSION

version v0.999.998.3

SYNOPSIS

    # get a Database object via MongoDB::MongoClient
    my $db   = $client->get_database("foo");

    # get a Collection via the Database object
    my $coll = $db->get_collection("people");

    # run a command on a database
    my $res = $db->run_command([ismaster => 1]);

DESCRIPTION

This class models a MongoDB database. Use it to construct MongoDB::Collection objects. It also provides the "run_command" method and some convenience methods that use it.

Generally, you never construct one of these directly with new. Instead, you call get_database on a MongoDB::MongoClient object.

USAGE

Error handling

Unless otherwise explictly documented, all methods throw exceptions if an error occurs. The error types are documented in MongoDB::Error.

To catch and handle errors, the Try::Tiny and Safe::Isa modules are recommended:

    use Try::Tiny;
    use Safe::Isa; # provides $_isa

    try {
        $db->run_command( @command )
    }
    catch {
        if ( $_->$_isa("MongoDB::DuplicateKeyError" ) {
            ...
        }
        else {
            ...
        }
    };

To retry failures automatically, consider using Try::Tiny::Retry.

ATTRIBUTES

name

The name of the database.

read_preference

A MongoDB::ReadPreference object. It may be initialized with a string corresponding to one of the valid read preference modes or a hash reference that will be coerced into a new MongoDB::ReadPreference object. By default it will be inherited from a MongoDB::MongoClient object.

write_concern

A MongoDB::WriteConcern object. It may be initialized with a hash reference that will be coerced into a new MongoDB::WriteConcern object. By default it will be inherited from a MongoDB::MongoClient object.

METHODS

collection_names

    my @collections = $database->collection_names;

Returns the list of collections in this database.

get_collection, coll

    my $collection = $database->get_collection('foo');
    my $collection = $database->get_collection('foo', $options);
    my $collection = $database->coll('foo', $options);

Returns a MongoDB::Collection for the given collection name within this database.

It takes an optional hash reference of options that are passed to the MongoDB::Collection constructor.

The coll method is an alias for get_collection.

get_gridfs

    my $grid = $database->get_gridfs;
    my $grid = $database->get_gridfs("fs");
    my $grid = $database->get_gridfs("fs", $options);

Returns a MongoDB::GridFS for storing and retrieving files from the database. Default prefix is "fs", making $grid->files "fs.files" and $grid->chunks "fs.chunks".

It takes an optional hash reference of options that are passed to the MongoDB::GridFS constructor.

See MongoDB::GridFS for more information.

drop

    $database->drop;

Deletes the database.

run_command

    my $result = $database->run_command([ some_command => 1 ]);

    my $result = $database->run_command(
        [ some_command => 1 ],
        { mode => 'secondaryPreferred' }
    );

This method runs a database command. The first argument must be a document with the command and its arguments. It should be given as an array reference of key-value pairs or a Tie::IxHash object with the command name as the first key. The use of a hash reference will only reliably work for commands without additional parameters.

By default, commands are run with a read preference of 'primary'. An optional second argument may specify an alternative read preference. If given, it must be a MongoDB::ReadPreference object or a hash reference that can be used to construct one.

It returns the result of the command (a hash reference) on success or throws a MongoDB::DatabaseError exception if the command fails.

For a list of possible database commands, run:

    my $commands = $db->run_command([listCommands => 1]);

There are a few examples of database commands in the "DATABASE COMMANDS" in MongoDB::Examples section. See also core documentation on database commands: http://dochub.mongodb.org/core/commands.

eval ($code, $args?, $nolock?)

    my $result = $database->eval('function(x) { return "hello, "+x; }', ["world"]);

Evaluate a JavaScript expression on the Mongo server. The $code argument can be a string or an instance of MongoDB::Code. The $args are an optional array of arguments to be passed to the $code function. $nolock (default false) prevents the eval command from taking the global write lock before evaluating the JavaScript.

eval is useful if you need to touch a lot of data lightly; in such a scenario the network transfer of the data could be a bottleneck. The $code argument must be a JavaScript function. $args is an array of parameters that will be passed to the function. $nolock is a boolean value. For more examples of using eval see http://www.mongodb.org/display/DOCS/Server-side+Code+Execution#Server-sideCodeExecution-Using{{db.eval%28%29}}.

DEPRECATIONS

The methods still exist, but are no longer documented. In a future version they will warn when used, then will eventually be removed.

• last_error

AUTHORS

• David Golden <david@mongodb.com>

• Mike Friedman <friedo@mongodb.com>

• Kristina Chodorow <kristina@mongodb.com>

• Florian Ragwitz <rafl@debian.org>

COPYRIGHT AND LICENSE

This software is Copyright (c) 2015 by MongoDB, Inc..

This is free software, licensed under:

  The Apache License, Version 2.0, January 2004

cpanm MongoDB

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install MongoDB