/ 
MongoDB-0.43
River stage two • 48 direct dependents • 56 total dependents
/ MongoDB::Collection

NAME

MongoDB::Collection - A Mongo collection

SYNOPSIS

An instance of a MongoDB collection.

# gets the foo collection
my $collection = $db->foo;

Collection names can be chained together to access subcollections. For instance, the collection foo.bar can be accessed with:

my $collection = $db->foo->bar;

You can also access collections with the "get_collection" in MongoDB::Database method.

SEE ALSO

Core documentation on collections: http://dochub.mongodb.org/core/collections.

ATTRIBUTES

name

The name of the collection.

full_name

The full_name of the collection, including the namespace of the database it's in.

STATIC METHODS

to_index_string ($keys)

$name = MongoDB::Collection::to_index_string({age : 1});

Takes a Tie::IxHash, hash reference, or array reference. Converts it into an index string.

METHODS

find($query)

my $cursor = $collection->find({ i => { '$gt' => 42 } });

Executes the given $query and returns a MongoDB::Cursor with the results. $query can be a hash reference, Tie::IxHash, or array reference (with an even number of elements).

The set of fields returned can be limited through the use of the MongoDB::Cursor::fields method on the resulting MongoDB::Cursor object. Other commonly used cursor methods are MongoDB::Cursor::limit, MongoDB::Cursor::skip, and MongoDB::Cursor::sort.

See also core documentation on querying: http://dochub.mongodb.org/core/find.

query($query, $attrs?)

Identical to MongoDB::Collection::find, described above.

my $cursor = $collection->query({ }, { limit => 10, skip => 10 });

my $cursor = $collection->query(
    { location => "Vancouver" },
    { sort_by  => { age => 1 } },
);

Valid query attributes are:

limit

Limit the number of results.

skip

Skip a number of results.

sort_by

Order results.

find_one ($query, $fields?)

my $object = $collection->find_one({ name => 'Resi' });
my $object = $collection->find_one({ name => 'Resi' }, { name => 1, age => 1});

Executes the given $query and returns the first object matching it. $query can be a hash reference, Tie::IxHash, or array reference (with an even number of elements). If $fields is specified, the resulting document will only include the fields given (and the _id field) which can cut down on wire traffic.

insert ($object, $options?)

my $id1 = $coll->insert({ name => 'mongo', type => 'database' });
my $id2 = $coll->insert({ name => 'mongo', type => 'database' }, {safe => 1});

Inserts the given $object into the database and returns it's id value. $object can be a hash reference, a reference to an array with an even number of elements, or a Tie::IxHash. The id is the _id value specified in the data or a MongoDB::OID.

The optional $options parameter can be used to specify if this is a safe insert. A safe insert will check with the database if the insert succeeded and croak if it did not. You can also check if the insert succeeded by doing an unsafe insert, then calling "last_error($options?)" in MongoDB::Database.

See also core documentation on insert: http://dochub.mongodb.org/core/insert.

batch_insert (\@array, $options)

my @ids = $collection->batch_insert([{name => "Joe"}, {name => "Fred"}, {name => "Sam"}]);

Inserts each of the documents in the array into the database and returns an array of their _id fields.

The optional $options parameter can be used to specify if this is a safe insert. A safe insert will check with the database if the insert succeeded and croak if it did not. You can also check if the inserts succeeded by doing an unsafe batch insert, then calling "last_error($options?)" in MongoDB::Database.

update (\%criteria, \%object, \%options?)

$collection->update({'x' => 3}, {'$inc' => {'count' => -1} }, {"upsert" => 1, "multiple" => 1});

Updates an existing $object matching $criteria in the database.

Returns 1 unless the safe option is set. If safe is set, this will return a hash of information about the update, including number of documents updated (n). If safe is set and the update fails, update will croak. You can also check if the update succeeded by doing an unsafe update, then calling "last_error($options?)" in MongoDB::Database.

update can take a hash reference of options. The options currently supported are:

upsert If no object matching $criteria is found, $object will be inserted.
multiple All of the documents that match $criteria will be updated, not just the first document found. (Only available with database version 1.1.3 and newer.)
safe If the update fails and safe is set, the update will croak.

See also core documentation on update: http://dochub.mongodb.org/core/update.

remove ($query?, $options?)

$collection->remove({ answer => { '$ne' => 42 } });

Removes all objects matching the given $query from the database. If no parameters are given, removes all objects from the collection (but does not delete indexes, as MongoDB::Collection::drop does).

Returns 1 unless the safe option is set. If safe is set and the remove succeeds, remove will return a hash of information about the remove, including how many documents were removed (n). If the remove fails and safe is set, remove will croak. You can also check if the remove succeeded by doing an unsafe remove, then calling "last_error($options?)" in MongoDB::Database.

remove can take a hash reference of options. The options currently supported are

just_one Only one matching document to be removed.
safe If the update fails and safe is set, this function will croak.

See also core documentation on remove: http://dochub.mongodb.org/core/remove.

ensure_index ($keys, $options?)

use boolean;
$collection->ensure_index({"foo" => 1, "bar" => -1}, { unique => true });

Makes sure the given $keys of this collection are indexed. $keys can be an array reference, hash reference, or Tie::IxHash. Tie::IxHash is prefered for multi-key indexes, so that the keys are in the correct order. 1 creates an ascending index, -1 creates a descending index.

If the safe option is not set, ensure_index will not return anything unless there is a socket error (in which case it will croak). If the safe option is set and the index creation fails, it will also croak. You can also check if the indexing succeeded by doing an unsafe index creation, then calling "last_error($options?)" in MongoDB::Database.

See the MongoDB::Indexing pod for more information on indexing.

save($doc, $options)

$collection->save({"author" => "joe"});
my $post = $collection->find_one;

$post->{author} = {"name" => "joe", "id" => 123, "phone" => "555-5555"};

$collection->save($post);

Inserts a document into the database if it does not have an _id field, upserts it if it does have an _id field.

safe = boolean>

If the save fails and safe is set, this function will croak.

The return types for this function are a bit of a mess, as it will return the _id if a new document was inserted, 1 if an upsert occurred, and croak if the safe option was set and an error occurred. You can also check if the save succeeded by doing an unsafe save, then calling "last_error($options?)" in MongoDB::Database.

count($query?)

my $n_objects = $collection->count({ name => 'Bob' });

Counts the number of objects in this collection that match the given $query. If no query is given, the total number of objects in the collection is returned.

validate

$collection->validate;

Asks the server to validate this collection. Returns a hash of the form:

{
    'ok' => '1',
    'ns' => 'foo.bar',
    'result' => info
}

where info is a string of information about the collection.

drop_indexes

$collection->drop_indexes;

Removes all indexes from this collection.

drop_index ($index_name)

$collection->drop_index('foo_1');

Removes an index called $index_name from this collection. Use MongoDB::Collection::get_indexes to find the index name.

get_indexes

my @indexes = $collection->get_indexes;

Returns a list of all indexes of this collection. Each index contains ns, name, and key fields of the form:

{
    'ns' => 'db_name.collection_name',
    'name' => 'index_name',
    'key' => {
        'key1' => dir1,
        'key2' => dir2,
        ...
        'keyN' => dirN
    }
}

where dirX is 1 or -1, depending on if the index is ascending or descending on that key.

drop

$collection->drop;

Deletes a collection as well as all of its indexes.

AUTHOR

Kristina Chodorow <kristina@mongodb.org>