Provided by: libmongodb-perl_1.2.2-1_amd64 
NAME
MongoDB::Collection - A MongoDB Collection
VERSION
version v1.2.2
SYNOPSIS
# get a Collection via the Database object
$coll = $db->get_collection("people");
# insert a document
$coll->insert_one( { name => "John Doe", age => 42 } );
# insert one or more documents
$coll->insert_many( \@documents );
# delete a document
$coll->delete_one( { name => "John Doe" } );
# update a document
$coll->update_one( { name => "John Doe" }, { '$inc' => { age => 1 } } );
# find a single document
$doc = $coll->find_one( { name => "John Doe" } )
# Get a MongoDB::Cursor for a query
$cursor = $coll->find( { age => 42 } );
# Cursor iteration
while ( my $doc = $cursor->next ) {
...
}
DESCRIPTION
This class models a MongoDB collection and provides an API for interacting with it.
Generally, you never construct one of these directly with "new". Instead, you call
"get_collection" on a MongoDB::Database 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 {
$coll->insert( $doc )
}
catch {
if ( $_->$_isa("MongoDB::DuplicateKeyError" ) {
...
}
else {
...
}
};
To retry failures automatically, consider using Try::Tiny::Retry.
Terminology
Document
A collection of key-value pairs. A Perl hash is a document. Array references with an
even number of elements and Tie::IxHash objects may also be used as documents.
Ordered document
Many MongoDB::Collection method parameters or options require an ordered document: an
ordered list of key/value pairs. Perl's hashes are not ordered and since Perl v5.18 are
guaranteed to have random order. Therefore, when an ordered document is called for, you
may use an array reference of pairs or a Tie::IxHash object. You may use a hash reference
if there is only one key/value pair.
Filter expression
A filter expression provides the query criteria
<http://docs.mongodb.org/manual/tutorial/query-documents/> to select a document for
deletion. It must be an "Ordered document".
ATTRIBUTES
database
The MongoDB::Database representing the database that contains the collection.
name
The name of the collection.
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::Database
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::Database 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::Database object.
max_time_ms
Specifies the default 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::Database
object.
METHODS
client
$client = $coll->client;
Returns the MongoDB::MongoClient object associated with this object.
full_name
$full_name = $coll->full_name;
Returns the full name of the collection, including the namespace of the database it's in
prefixed with a dot character. E.g. collection "foo" in database "test" would result in a
"full_name" of "test.foo".
indexes
$indexes = $collection->indexes;
$collection->indexes->create_one( [ x => 1 ], { unique => 1 } );
$collection->indexes->drop_all;
Returns a MongoDB::IndexView object for managing the indexes associated with the
collection.
clone
$coll2 = $coll1->clone( write_concern => { w => 2 } );
Constructs a copy of the original collection, but allows changing attributes in the copy.
with_codec
$coll2 = $coll1->with_codec( $new_codec );
$coll2 = $coll1->with_codec( prefer_numeric => 1 );
Constructs a copy of the original collection, but clones the "bson_codec". If given an
object that does "encode_one" and "decode_one", it is equivalent to:
$coll2 = $coll1->clone( bson_codec => $new_codec );
If given a hash reference or a list of key/value pairs, it is equivalent to:
$coll2 = $coll1->clone(
bson_codec => $coll1->bson_codec->clone( @list )
);
insert_one
$res = $coll->insert_one( $document );
$res = $coll->insert_one( $document, $options );
$id = $res->inserted_id;
Inserts a single document into the database and returns a MongoDB::InsertOneResult or
MongoDB::UnacknowledgedResult object.
If no "_id" field is present, one will be added when a document is serialized for the
database without modifying the original document. The generated "_id" may be retrieved
from the result object.
An optional hash reference of options may be given.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
insert_many
$res = $coll->insert_many( [ @documents ] );
$res = $coll->insert_many( [ @documents ], { ordered => 0 } );
Inserts each of the documents in an array reference into the database and returns a
MongoDB::InsertManyResult or MongoDB::UnacknowledgedResult. This is syntactic sugar for
doing a MongoDB::BulkWrite operation.
If no "_id" field is present, one will be added when a document is serialized for the
database without modifying the original document. The generated "_id" may be retrieved
from the result object.
An optional hash reference of options may be provided.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
• "ordered" – when true, the server will halt insertions after the first error (if any).
When false, all documents will be processed and any error will only be thrown after
all insertions are attempted. The default is true.
On MongoDB servers before version 2.6, "insert_many" bulk operations are emulated with
individual inserts to capture error information. On 2.6 or later, this method will be
significantly faster than individual "insert_one" calls.
delete_one
$res = $coll->delete_one( $filter );
$res = $coll->delete_one( { _id => $id } );
Deletes a single document that matches a filter expression and returns a
MongoDB::DeleteResult or MongoDB::UnacknowledgedResult object.
delete_many
$res = $coll->delete_many( $filter );
$res = $coll->delete_many( { name => "Larry" } );
Deletes all documents that match a filter expression and returns a MongoDB::DeleteResult
or MongoDB::UnacknowledgedResult object.
replace_one
$res = $coll->replace_one( $filter, $replacement );
$res = $coll->replace_one( $filter, $replacement, { upsert => 1 } );
Replaces one document that matches a filter expression and returns a MongoDB::UpdateResult
or MongoDB::UnacknowledgedResult object.
The replacement document must not have any field-update operators in it (e.g. $set).
A hash reference of options may be provided.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
• "upsert" – defaults to false; if true, a new document will be added if one is not
found
update_one
$res = $coll->update_one( $filter, $update );
$res = $coll->update_one( $filter, $update, { upsert => 1 } );
Updates one document that matches a filter expression and returns a MongoDB::UpdateResult
or MongoDB::UnacknowledgedResult object.
The update document must have only field-update operators in it (e.g. $set).
A hash reference of options may be provided.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
• "upsert" – defaults to false; if true, a new document will be added if one is not
found by taking the filter expression and applying the update document operations to
it prior to insertion.
update_many
$res = $coll->update_many( $filter, $update );
$res = $coll->update_many( $filter, $update, { upsert => 1 } );
Updates one or more documents that match a filter expression and returns a
MongoDB::UpdateResult or MongoDB::UnacknowledgedResult object.
The update document must have only field-update operators in it (e.g. $set).
A hash reference of options may be provided.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
• "upsert" – defaults to false; if true, a new document will be added if one is not
found by taking the filter expression and applying the update document operations to
it prior to insertion.
find
$cursor = $coll->find( $filter );
$cursor = $coll->find( $filter, $options );
$cursor = $coll->find({ i => { '$gt' => 42 } }, {limit => 20});
Executes a query with a filter expression and returns a "MongoDB::Cursor" object.
The query can be customized using MongoDB::Cursor methods, or with an optional hash
reference of options.
Valid options include:
• "allowPartialResults" - get partial results from a mongos if some shards are down
(instead of throwing an error).
• "batchSize" – the number of documents to return per batch.
• "comment" – attaches a comment to the query. If $comment also exists in the
"modifiers" document, the comment field overwrites $comment.
• "cursorType" – indicates the type of cursor to use. It must be one of three string
values: 'non_tailable' (the default), 'tailable', and 'tailable_await'.
• "limit" – the maximum number of documents to return.
• "maxAwaitTimeMS" – the maximum amount of time for the server to wait on new documents
to satisfy a tailable cursor query. This only applies to a "cursorType" of
'tailable_await'; the option is otherwise ignored. (Note, this will be ignored for
servers before version 3.2.)
• "maxTimeMS" – the maximum amount of time to allow the query to run. If $maxTimeMS also
exists in the modifiers document, the "maxTimeMS" field overwrites $maxTimeMS. (Note,
this will be ignored for servers before version 2.6.)
• "modifiers" – a hash reference of query modifiers
<http://docs.mongodb.org/manual/reference/operator/query-modifier/> modifying the
output or behavior of a query.
• "noCursorTimeout" – if true, prevents the server from timing out a cursor after a
period of inactivity
• "projection" - a hash reference defining fields to return. See "limit fields to return
<http://docs.mongodb.org/manual/tutorial/project-fields-from-query-results/>" in the
MongoDB documentation for details.
• "skip" – the number of documents to skip before returning.
• "sort" – an ordered document defining the order in which to return matching documents.
If $orderby also exists in the modifiers document, the sort field overwrites $orderby.
See docs for $orderby
<http://docs.mongodb.org/manual/reference/operator/meta/orderby/>.
For more information, see the Read Operations Overview
<http://docs.mongodb.org/manual/core/read-operations-introduction/> in the MongoDB
documentation.
Note, a MongoDB::Cursor object holds the query and does not issue the query to the server
until the result method is called on it or until an iterator method like next is called.
Performance will be better directly on a MongoDB::QueryResult object:
my $query_result = $coll->find( $filter )->result;
while ( my $next = $query_result->next ) {
...
}
find_one
$doc = $collection->find_one( $filter, $projection );
$doc = $collection->find_one( $filter, $projection, $options );
Executes a query with a filter expression and returns a single document.
If a projection argument is provided, it must be a hash reference specifying fields to
return. See Limit fields to return <http://docs.mongodb.org/manual/tutorial/project-
fields-from-query-results/> in the MongoDB documentation for details.
If only a filter is provided or if the projection document is an empty hash reference, all
fields will be returned.
my $doc = $collection->find_one( $filter );
my $doc = $collection->find_one( $filter, {}, $options );
A hash reference of options may be provided as a third argument. Valid keys include:
• "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.)
• "sort" – an ordered document defining the order in which to return matching documents.
If $orderby also exists in the modifiers document, the sort field overwrites $orderby.
See docs for $orderby
<http://docs.mongodb.org/manual/reference/operator/meta/orderby/>.
See also core documentation on querying: <http://docs.mongodb.org/manual/core/read/>.
find_id
$doc = $collection->find_id( $id );
$doc = $collection->find_id( $id, $projection );
$doc = $collection->find_id( $id, $projection, $options );
Executes a query with a filter expression of "{ _id => $id }" and returns a single
document.
See the find_one documentation for details on the $projection and $options parameters.
See also core documentation on querying: <http://docs.mongodb.org/manual/core/read/>.
find_one_and_delete
$doc = $coll->find_one_and_delete( $filter );
$doc = $coll->find_one_and_delete( $filter, $options );
Given a filter expression, this deletes a document from the database and returns it as it
appeared before it was deleted.
A hash reference of options may be provided. Valid keys include:
• "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.)
• "projection" - a hash reference defining fields to return. See "limit fields to return
<http://docs.mongodb.org/manual/tutorial/project-fields-from-query-results/>" in the
MongoDB documentation for details.
• "sort" – an ordered document defining the order in which to return matching documents.
See docs for $orderby
<http://docs.mongodb.org/manual/reference/operator/meta/orderby/>.
find_one_and_replace
$doc = $coll->find_one_and_replace( $filter, $replacement );
$doc = $coll->find_one_and_replace( $filter, $replacement, $options );
Given a filter expression and a replacement document, this replaces a document from the
database and returns it as it was either right before or right after the replacement. The
default is 'before'.
The replacement document must not have any field-update operators in it (e.g. $set).
A hash reference of options may be provided. Valid keys include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
• "maxTimeMS" – the maximum amount of time in milliseconds to allow the command to run.
• "projection" - a hash reference defining fields to return. See "limit fields to return
<http://docs.mongodb.org/manual/tutorial/project-fields-from-query-results/>" in the
MongoDB documentation for details.
• "returnDocument" – either the string 'before' or 'after', to indicate whether the
returned document should be the one before or after replacement. The default is
'before'.
• "sort" – an ordered document defining the order in which to return matching documents.
See docs for $orderby
<http://docs.mongodb.org/manual/reference/operator/meta/orderby/>.
• "upsert" – defaults to false; if true, a new document will be added if one is not
found
find_one_and_update
$doc = $coll->find_one_and_update( $filter, $update );
$doc = $coll->find_one_and_update( $filter, $update, $options );
Given a filter expression and a document of update operators, this updates a single
document and returns it as it was either right before or right after the update. The
default is 'before'.
The update document must contain only field-update operators (e.g. $set).
A hash reference of options may be provided. Valid keys include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
• "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.)
• "projection" - a hash reference defining fields to return. See "limit fields to return
<http://docs.mongodb.org/manual/tutorial/project-fields-from-query-results/>" in the
MongoDB documentation for details.
• "returnDocument" – either the string 'before' or 'after', to indicate whether the
returned document should be the one before or after replacement. The default is
'before'.
• "sort" – an ordered document defining the order in which to return matching documents.
See docs for $orderby
<http://docs.mongodb.org/manual/reference/operator/meta/orderby/>.
• "upsert" – defaults to false; if true, a new document will be added if one is not
found
aggregate
@pipeline = (
{ '$group' => { _id => '$state,' totalPop => { '$sum' => '$pop' } } },
{ '$match' => { totalPop => { '$gte' => 10 * 1000 * 1000 } } }
);
$result = $collection->aggregate( \@pipeline );
$result = $collection->aggregate( \@pipeline, $options );
Runs a query using the MongoDB 2.2+ aggregation framework and returns a
MongoDB::QueryResult object.
The first argument must be an array-ref of aggregation pipeline
<http://docs.mongodb.org/manual/core/aggregation-pipeline/> documents. Each pipeline
document must be a hash reference.
A hash reference of options may be provided. Valid keys include:
• "allowDiskUse" – if, true enables writing to temporary files.
• "batchSize" – the number of documents to return per batch.
• "bypassDocumentValidation" - skips document validation, if enabled. (Note, this will
be ignored for servers before version 3.2.)
• "explain" – if true, return a single document with execution information.
• "maxTimeMS" – the maximum amount of time in milliseconds to allow the command to run.
(Note, this will be ignored for servers before version 2.6.)
Note MongoDB 2.6+ added the '$out' pipeline operator. If this operator is used to write
aggregation results directly to a collection, an empty result will be returned. Create a
new collection> object to query the generated result collection. When $out is used, the
command is treated as a write operation and read preference is ignored.
See Aggregation <http://docs.mongodb.org/manual/aggregation/> in the MongoDB manual for
more information on how to construct aggregation queries.
Note The use of aggregation cursors is automatic based on your server version. However,
if migrating a sharded cluster from MongoDB 2.4 to 2.6 or later, you must upgrade your
mongod servers first before your mongos routers or aggregation queries will fail. As a
workaround, you may pass "cursor => undef" as an option.
count
$count = $coll->count( $filter );
$count = $coll->count( $filter, $options );
Returns a count of documents matching a filter expression.
A hash reference of options may be provided. Valid keys include:
• "hint" – specify an index to use
<http://docs.mongodb.org/manual/reference/command/count/#specify-the-index-to-use>;
must be a string, array reference, hash reference or Tie::IxHash object.
• "limit" – the maximum number of documents to count.
• "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.)
• "skip" – the number of documents to skip before counting documents.
NOTE: On a sharded cluster, "count" can result in an inaccurate count if orphaned
documents exist or if a chunk migration is in progress. See count command documentation
<http://docs.mongodb.org/manual/reference/command/count/#behavior> for details and a work-
around using "aggregate".
distinct
$result = $coll->distinct( $fieldname );
$result = $coll->distinct( $fieldname, $filter );
$result = $coll->distinct( $fieldname, $filter, $options );
Returns a MongoDB::QueryResult object that will provide distinct values for a specified
field name.
The query may be limited by an optional filter expression.
A hash reference of options may be provided. Valid keys include:
• "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.)
See documentation for the distinct command
<http://docs.mongodb.org/manual/reference/command/distinct/> for details.
parallel_scan
@result_objs = $collection->parallel_scan(10);
Returns one or more MongoDB::QueryResult objects to scan the collection in parallel. The
argument is the maximum number of MongoDB::QueryResult objects to return and must be a
positive integer between 1 and 10,000.
As long as the collection is not modified during scanning, each document will appear only
once in one of the cursors' result sets.
Note: the server may return fewer cursors than requested, depending on the underlying
storage engine and resource availability.
rename
$newcollection = $collection->rename("mynewcollection");
Renames the collection. If a collection already exists with the new collection name, this
method will throw an exception.
It returns a new MongoDB::Collection object corresponding to the renamed collection.
drop
$collection->drop;
Deletes a collection as well as all of its indexes.
ordered_bulk
$bulk = $coll->ordered_bulk;
$bulk->insert( $doc1 );
$bulk->insert( $doc2 );
...
$result = $bulk->execute;
Returns a MongoDB::BulkWrite object to group write operations into fewer network round-
trips. This method creates an ordered operation, where operations halt after the first
error. See MongoDB::BulkWrite for more details.
The method "initialize_ordered_bulk_op" may be used as an alias.
A hash reference of options may be provided.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
unordered_bulk
This method works just like "ordered_bulk" except that the order that operations are sent
to the database is not guaranteed and errors do not halt processing. See
MongoDB::BulkWrite for more details.
The method "initialize_unordered_bulk_op" may be used as an alias.
A hash reference of options may be provided.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
bulk_write
$res = $coll->bulk_write( [ @requests ], $options )
This method provides syntactic sugar to construct and execute a bulk operation directly,
without using "initialize_ordered_bulk" or "initialize_unordered_bulk" to generate a
MongoDB::BulkWrite object and then calling methods on it. It returns a
MongoDB::BulkWriteResponse object just like the MongoDB::BulkWrite execute method.
The first argument must be an array reference of requests. Requests consist of pairs of a
MongoDB::Collection write method name (e.g. "insert_one", "delete_many") and an array
reference of arguments to the corresponding method name. They may be given as pairs, or
as hash or array references:
# pairs -- most efficient
@requests = (
insert_one => [ { x => 1 } ],
replace_one => [ { x => 1 }, { x => 4 } ],
delete_one => [ { x => 4 } ],
update_many => [ { x => { '$gt' => 5 } }, { '$inc' => { x => 1 } } ],
);
# hash references
@requests = (
{ insert_one => [ { x => 1 } ] },
{ replace_one => [ { x => 1 }, { x => 4 } ] },
{ delete_one => [ { x => 4 } ] },
{ update_many => [ { x => { '$gt' => 5 } }, { '$inc' => { x => 1 } } ] },
);
# array references
@requests = (
[ insert_one => [ { x => 1 } ] ],
[ replace_one => [ { x => 1 }, { x => 4 } ] ],
[ delete_one => [ { x => 4 } ] ],
[ update_many => [ { x => { '$gt' => 5 } }, { '$inc' => { x => 1 } } ] ],
);
Valid method names include "insert_one", "insert_many", "delete_one", "delete_many"
"replace_one", "update_one", "update_many".
An optional hash reference of options may be provided.
Valid options include:
• "bypassDocumentValidation" - skips document validation, if enabled; this is ignored
for MongoDB servers older than version 3.2.
• "ordered" – when true, the bulk operation is executed like "initialize_ordered_bulk".
When false, the bulk operation is executed like "initialize_unordered_bulk". The
default is true.
See MongoDB::BulkWrite for more details on bulk writes. Be advised that the legacy Bulk
API method names differ slightly from MongoDB::Collection method names.
DEPRECATIONS
With the introduction of the common driver CRUD API, these legacy methods have been
deprecated:
• batch_insert
• find_and_modify
• insert
• query
• remove
• update
• save
The "get_collection" method is deprecated; it implied a 'subcollection' relationship that
is purely notional.
The "ensure_index", "drop_indexes", "drop_index", and "get_index" methods are deprecated.
The new MongoDB::IndexView class is accessible through the "indexes" method, and offer
greater consistency in behavior across drivers.
The "validate" method is deprecated as the return value was inconsistent over time. Users
who need it should execute it via "run_command" instead.
The methods still exist, but are no longer documented. In a future version they will warn
when used, then will eventually be removed.
AUTHORS
• David Golden <david@mongodb.com>
• Mike Friedman <friedo@friedo.com>
• Kristina Chodorow <k.chodorow@gmail.com>
• Florian Ragwitz <rafl@debian.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2016 by MongoDB, Inc..
This is free software, licensed under:
The Apache License, Version 2.0, January 2004