NAME
MongoDB::Collection - A MongoDB Collection
VERSION
version 0.702.2
SYNOPSIS
An instance of a MongoDB collection.
# gets the foo collection
my $collection = $db->get_collection( 'foo' );
Collection names can be chained together to access subcollections. For instance, the collection foo.bar
can be accessed with either:
my $collection = $db->get_collection( 'foo' )->get_collection( 'bar' );
or
my $collection = $db->get_collection( 'foo.bar' );
ATTRIBUTES
name
The name of the collection.
full_name
The full_name of the collection, including the namespace of the database it's in.
METHODS
get_collection ($name)
my $collection = $database->get_collection('foo');
Returns a MongoDB::Collection for the collection called $name
within this collection.
find($query)
my $cursor = $collection->find({ i => { '$gt' => 42 } });
Executes the given $query
and returns a MongoDB::Cursor
with the results. $query
can be a hash reference, Tie::IxHash, or array reference (with an even number of elements).
The set of fields returned can be limited through the use of the MongoDB::Cursor::fields
method on the resulting MongoDB::Cursor object. Other commonly used cursor methods are MongoDB::Cursor::limit
, MongoDB::Cursor::skip
, and MongoDB::Cursor::sort
.
See also core documentation on querying: http://docs.mongodb.org/manual/core/read/.
query($query, $attrs?)
Identical to MongoDB::Collection::find
, described above.
my $cursor = $collection->query->limit(10)->skip(10);
my $cursor = $collection->query({ location => "Vancouver" })->sort({ age => 1 });
Valid query attributes are:
- limit
-
Limit the number of results.
- skip
-
Skip a number of results.
- sort_by
-
Order results.
find_one($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://docs.mongodb.org/manual/core/create/.
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://docs.mongodb.org/manual/core/update/.
find_and_modify
my $result = $collection->find_and_modify( { query => { ... }, update => { ... } } );
Perform an atomic update. find_and_modify
guarantees that nothing else will come along and change the queried documents before the update is performed.
Returns the old version of the document, unless new =
1> is specified. If no documents match the query, it returns nothing.
aggregate
my $result = $collection->aggregate( [ ... ] );
Run a query using the MongoDB 2.2+ aggregation framework. The argument is an array-ref of aggregation pipeline operators. Returns an array-ref containing the results of the query. See Aggregation in the MongoDB manual for more information on how to construct aggregation queries.
rename ("newcollectionname")
my $newcollection = $collection->rename("mynewcollection");
Renames the collection. It expects that the new name is currently not in use.
Returns the new collection. If a collection already exists with that new collection name this will die.
save($doc, $options)
$collection->save({"author" => "joe"});
my $post = $collection->find_one;
$post->{author} = {"name" => "joe", "id" => 123, "phone" => "555-5555"};
$collection->save( $post );
$collection->save( $post, { safe => 1 } )
Inserts a document into the database if it does not have an _id field, upserts it if it does have an _id field.
The return types for this function are a bit of a mess, as it will return the _id if a new document was inserted, 1 if an upsert occurred, and croak if the safe option was set and an error occurred. You can also check if the save succeeded by doing an unsafe save, then calling "last_error($options?)" in MongoDB::Database.
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://docs.mongodb.org/manual/core/delete/.
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. $keys
can be an array reference, hash reference, or Tie::IxHash
. Tie::IxHash
is preferred for multi-key indexes, so that the keys are in the correct order. 1 creates an ascending index, -1 creates a descending index.
If the safe
option is not set, ensure_index
will not return anything unless there is a socket error (in which case it will croak). If the safe
option is set and the index creation fails, it will also croak. You can also check if the indexing succeeded by doing an unsafe index creation, then calling "last_error($options?)" in MongoDB::Database.
See the MongoDB::Indexing pod for more information on indexing.
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.
AUTHORS
Florian Ragwitz <rafl@debian.org>
Kristina Chodorow <kristina@mongodb.org>
Mike Friedman <friedo@mongodb.com>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2013 by MongoDB, Inc..
This is free software, licensed under:
The Apache License, Version 2.0, January 2004