man MongoDB::Database (3): A MongoDB Database

VERSION

version v1.2.3

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 explicitly 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.

read_concern

A MongoDB::ReadConcern object. May be initialized with a hash reference or a string that will be coerced into the level of read concern.

By default it will be inherited from a MongoDB::MongoClient object.

max_time_ms

Specifies the maximum amount of time in milliseconds that the server should use for working on a query.

Note: this will only be used for server versions 2.6 or greater, as that was when the $maxTimeMS meta-operator was introduced.

bson_codec

An object that provides the "encode_one" and "decode_one" methods, such as from MongoDB::BSON. It may be initialized with a hash reference that will be coerced into a new MongoDB::BSON object. By default it will be inherited from a MongoDB::MongoClient object.

METHODS

list_collections

    $result = $coll->list_collections( $filter );
    $result = $coll->list_collections( $filter, $options );

Returns a MongoDB::QueryResult object to iterate over collection description documents. These will contain "name" and "options" keys like so:

    use boolean;
    {
        name => "my_capped_collection",
        options => {
            capped => true,
            size => 10485760,
        }
    },

An optional filter document may be provided, which cause only collection description documents matching a filter expression to be returned. See the listCollections command documentation <http://docs.mongodb.org/manual/reference/command/listCollections/> for more details on filtering for specific collections.

A hash reference of options may be provided. Valid keys include:

"batchSize" – the number of documents to return per batch.
"maxTimeMS" – the maximum amount of time in milliseconds to allow the command to run. (Note, this will be ignored for servers before version 2.6.)

collection_names

    my @collections = $database->collection_names;

Returns the list of collections in this database.

Warning: if the number of collections is very large, this will return a very large result. Use ``list_collections'' to iterate over collections instead.

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

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 <[email protected]>
Mike Friedman <[email protected]>
Kristina Chodorow <[email protected]>
Florian Ragwitz <[email protected]>

COPYRIGHT AND LICENSE

This is free software, licensed under:

  The Apache License, Version 2.0, January 2004