Class: Mongo::Database

Relationships & Source Files
Namespace Children
Classes: `View`
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, Forwardable
Instance Chain: self, `Retryable`
Inherits:	Object
Defined in:	lib/mongo/database.rb, lib/mongo/database/view.rb

Overview

Represents a database on the db server and operations that can execute on it at this level.

Since:

2.0.0

Constant Summary

ADMIN =

The admin database name.
Since:
- 2.0.0
# File 'lib/mongo/database.rb', line 33
```
'admin'.freeze
```
COMMAND =

The “collection” that database commands operate against.
Since:
- 2.0.0
# File 'lib/mongo/database.rb', line 38
```
'$cmd'.freeze
```
DATABASES =

Databases constant.
Since:
- 2.1.0
# File 'lib/mongo/database.rb', line 54
```
'databases'.freeze
```
DEFAULT_OPTIONS =

The default database options.
Since:
- 2.0.0
# File 'lib/mongo/database.rb', line 43
```
Options::Redacted.new(:database => ADMIN).freeze
```
NAME =

Deprecated.

Database name field constant.
Since:
- 2.1.0
# File 'lib/mongo/database.rb', line 49
```
'name'.freeze
```
NAMESPACES =

The name of the collection that holds all the collection names.
Since:
- 2.0.0
# File 'lib/mongo/database.rb', line 59
```
'system.namespaces'.freeze
```

Class Method Summary

.create(client) ⇒ Database Internal use only Internal use only

Create a database for the provided client, for use when we don’t want the client’s original database instance to be the same.
.new(client, name, options = {}) ⇒ Database constructor

Instantiate a new database object.

Instance Attribute Summary

#client ⇒ Client readonly
#name ⇒ String readonly
#options ⇒ Hash readonly

Instance Method Summary

#==(other) ⇒ true, false

Check equality of the database object against another.
#[](collection_name, options = {}) ⇒ Mongo::Collection (also: #collection)

Get a collection in this database by the provided name.
#aggregate(pipeline, options = {}) ⇒ Collection::View::Aggregation

Perform an aggregation on the database.
#cluster ⇒ Mongo::Server
#collection(collection_name, options = {})

Alias for #[].
#collection_names(options = {}) ⇒ Array<String>

Get all the names of the non-system collections in the database.
#collections(options = {}) ⇒ Array<Mongo::Collection>

Get all the non-system collections that belong to this database.
#command(operation, opts = {}) ⇒ Mongo::Operation::Result

Execute a command on the database.
#drop(options = {}) ⇒ Result

Drop the database and all its associated information.
#fs(options = {}) ⇒ Grid::FSBucket

Get the Grid “filesystem” for this database.
#inspect ⇒ String

Get a pretty printed string inspection for the database.
#list_collections(options = {}) ⇒ Array<Hash>

Get info on all the non-system collections in the database.
#read_command(operation, opts = {}) ⇒ Hash Internal use only Internal use only

Execute a read command on the database, retrying the read if necessary.
#users ⇒ View::User

Get the user view for this database.
#watch(pipeline = [], options = {}) ⇒ ChangeStream

As of version 3.6 of the MongoDB server, a “$changeStream“ pipeline stage is supported in the aggregation framework.

`Retryable` - Included

#read_worker	Returns the read worker for handling retryable reads.
#select_server	This is a separate method to make it possible for the test suite to assert that server selection is performed during retry attempts.
#write_worker	Returns the write worker for handling retryable writes.

Constructor Details

.new(client, name, options = {}) ⇒ `Database`

Instantiate a new database object.

Examples:

Instantiate the database.

Mongo::Database.new(client, :test)

Parameters:

client (Mongo::Client) —

The driver client.
name (String, Symbol) —

The name of the database.
options (Hash) (defaults to: {}) —

The options.

Raises:

(Mongo::Database::InvalidName) —

If the name is nil.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 316


def initialize(client, name, options = {})
  raise Error::InvalidDatabaseName.new unless name
  if Lint.enabled? && !(name.is_a?(String) || name.is_a?(Symbol))
    raise "Database name must be a string or a symbol: #{name}"
  end
  @client = client
  @name = name.to_s.freeze
  @options = options.freeze
end

Class Method Details

.create(client) ⇒ `Database`

This method is for internal use only.

Create a database for the provided client, for use when we don’t want the client’s original database instance to be the same.

Examples:

Create a database for the client.

Database.create(client)

Parameters:

client (Client) —

The client to create on.

Returns:

(Database) —

The database.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 496


def self.create(client)
  database = Database.new(client, client.options[:database], client.options)
  client.instance_variable_set(:@database, database)
end

Instance Attribute Details

#client ⇒ Client (readonly)

Returns:

(Client) —

client The database client.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 62


attr_reader :client

#name ⇒ `String` (readonly)

Returns:

(String) —

name The name of the database.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 65


attr_reader :name

#options ⇒ `Hash` (readonly)

Returns:

(Hash) —

options The options.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 68


attr_reader :options

Instance Method Details

#==(other) ⇒ `true`, `false`

Check equality of the database object against another. Will simply check if the names are the same.

Examples:

Check database equality.

database == other

Parameters:

other (Object) —

The object to check against.

Returns:

(true, false) —

If the objects are equal.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 94


def ==(other)
  return false unless other.is_a?(Database)
  name == other.name
end

#[](collection_name, options = {}) ⇒ Mongo::Collection Also known as: #collection

Get a collection in this database by the provided name.

Examples:

Get a collection.

database[:users]

Parameters:

collection_name (String, Symbol) —

The name of the collection.
options (Hash) (defaults to: {}) —

The options to the collection.

Returns:

(Mongo::Collection) —

The collection object.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 110


def [](collection_name, options = {})
  if options[:server_api]
    raise ArgumentError, 'The :server_api option cannot be specified for collection objects. It can only be specified on Client level'
  end
  Collection.new(self, collection_name, options)
end

#aggregate(pipeline, options = {}) ⇒ Collection::View::Aggregation

Perform an aggregation on the database.

Examples:

Perform an aggregation.

collection.aggregate([ { "$listLocalSessions" => {} } ])

Parameters:

pipeline (Array<Hash>) —

The aggregation pipeline.
options (Hash) (defaults to: {}) —

The aggregation options.

Options Hash (options):

:allow_disk_use (true, false) —

Set to true if disk usage is allowed during the aggregation.
:batch_size (Integer) —

The number of documents to return per batch.
:bypass_document_validation (true, false) —

Whether or not to skip document level validation.
:collation (Hash) —

The collation to use.
:comment (Object) —

A user-provided comment to attach to this command.
:hint (String) —

The index to use for the aggregation.
:max_time_ms (Integer) —

The maximum amount of time in milliseconds to allow the aggregation to run.
:use_cursor (true, false) —

Indicates whether the command will request that the server provide results using a cursor. Note that as of server version 3.6, aggregations always provide results using a cursor and this option is therefore not valid.
:session (Session) —

The session to use.

Returns:

(Collection::View::Aggregation) —

The aggregation object.

Since:

2.10.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 403


def aggregate(pipeline, options = {})
  View.new(self).aggregate(pipeline, options)
end

#cluster ⇒ Mongo::Server

Returns:

(Mongo::Server) —

Get the primary server from the cluster.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 80


def_delegators :cluster,
               :next_primary

#collection(collection_name, options = {})

Alias for #[].

[ GitHub ]

# File 'lib/mongo/database.rb', line 116


alias_method :collection, :[]

#collection_names(options = {}) ⇒ `Array`<`String`>

Note:

The set of returned collection names depends on the version of MongoDB server that fulfills the request.

Get all the names of the non-system collections in the database.

Parameters:

options (Hash) (defaults to: {})

Options Hash (options):

:filter (Hash) —

A filter on the collections returned.
:authorized_collections (true, false) —

A flag, when set to true and used with nameOnly: true, that allows a user without the required privilege to run the command when access control is enforced
:comment (Object) —

A user-provided comment to attach to this command.

See mongodb.com/docs/manual/reference/command/listCollections/ for more information and usage.

Returns:

(Array<String>) —

Names of the collections.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 138


def collection_names(options = {})
  View.new(self).collection_names(options)
end

#collections(options = {}) ⇒ `Array`<Mongo::Collection>

Note:

The set of returned collections depends on the version of MongoDB server that fulfills the request.

Get all the non-system collections that belong to this database.

Parameters:

options (Hash) (defaults to: {})

Options Hash (options):

:filter (Hash) —

A filter on the collections returned.
:authorized_collections (true, false) —

A flag, when set to true and used with name_only: true, that allows a user without the required privilege to run the command when access control is enforced.
:comment (Object) —

A user-provided comment to attach to this command.

See mongodb.com/docs/manual/reference/command/listCollections/ for more information and usage.

Returns:

(Array<Mongo::Collection>) —

The collections.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 191


def collections(options = {})
  collection_names(options).map { |name| collection(name) }
end

#command(operation, opts = {}) ⇒ Mongo::Operation::Result

Execute a command on the database.

Examples:

Execute a command.

database.command(:hello => 1)

Parameters:

operation (Hash) —

The command to execute.
opts (Hash) (defaults to: {}) —

The command options.

Options Hash (opts):

:read (Hash) —

The read preference for this command.
:session (Session) —

The session to use for this command.
:execution_options (Hash) —
Options to pass to the code that executes this command. This is an internal option and is subject to change.
- :deserialize_as_bson [ Boolean ] Whether to deserialize the response to this command using BSON types intead of native Ruby types wherever possible.

Returns:

(Mongo::Operation::Result) —

The result of the command execution.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 213


def command(operation, opts = {})
  opts = opts.dup
  execution_opts = opts.delete(:execution_options) || {}

  txn_read_pref = if opts[:session] && opts[:session].in_transaction?
    opts[:session].txn_read_preference
  else
    nil
  end
  txn_read_pref ||= opts[:read] || ServerSelector::PRIMARY
  Lint.validate_underscore_read_preference(txn_read_pref)
  selector = ServerSelector.get(txn_read_pref)

  client.send(:with_session, opts) do |session|
    server = selector.select_server(cluster, nil, session)
    op = Operation::Command.new(
      :selector => operation,
      :db_name => name,
      :read => selector,
      :session => session
    )

    op.execute(server,
      context: Operation::Context.new(client: client, session: session),
      options: execution_opts)
  end
end

#drop(options = {}) ⇒ `Result`

Drop the database and all its associated information.

Examples:

Drop the database.

database.drop

Parameters:

options (Hash) (defaults to: {}) —

The options for the operation.
opts (Hash) —

a customizable set of options

Options Hash (options):

:session (Session) —

The session to use for the operation.

Returns:

(Result) —

The result of the command.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 287


def drop(options = {})
  operation = { :dropDatabase => 1 }
  client.send(:with_session, options) do |session|
    write_concern = if options[:write_concern]
      WriteConcern.get(options[:write_concern])
    else
      self.write_concern
    end
    Operation::DropDatabase.new({
      selector: operation,
      db_name: name,
      write_concern: write_concern,
      session: session
    }).execute(next_primary(nil, session), context: Operation::Context.new(client: client, session: session))
  end
end

#fs(options = {}) ⇒ Grid::FSBucket

Get the Grid “filesystem” for this database.

Parameters:

options (Hash) (defaults to: {}) —

The GridFS options.

Options Hash (options):

:bucket_name (String) —

The prefix for the files and chunks collections.
:chunk_size (Integer) —

Override the default chunk size.
:fs_name (String) —

The prefix for the files and chunks collections.
:read (String) —

The read preference.
:session (Session) —

The session to use.
:write (Hash) —

Deprecated. Equivalent to :write_concern option.
:write_concern (Hash) —

The write concern options. Can be :w => Integer|String, :fsync => Boolean, :j => Boolean.

Returns:

(Grid::FSBucket) —

The GridFS for the database.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 358


def fs(options = {})
  Grid::FSBucket.new(self, options)
end

#inspect ⇒ `String`

Get a pretty printed string inspection for the database.

Examples:

Inspect the database.

database.inspect

Returns:

(String) —

The database inspection.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 334


def inspect
  "#<Mongo::Database:0x#{object_id} name=#{name}>"
end

#list_collections(options = {}) ⇒ `Array`<`Hash`>

Note:

The set of collections returned, and the schema of the information hash per collection, depends on the MongoDB server version that fulfills the request.

Get info on all the non-system collections in the database.

Parameters:

options (Hash) (defaults to: {})

Options Hash (options):

:filter (Hash) —

A filter on the collections returned.
:name_only (true, false) —

Indicates whether command should return just collection/view names and type or return both the name and other information
:authorized_collections (true, false) —

A flag, when set to true and used with nameOnly: true, that allows a user without the required privilege to run the command when access control is enforced.
:comment (Object) —

A user-provided comment to attach to this command.

See mongodb.com/docs/manual/reference/command/listCollections/ for more information and usage.

Returns:

(Array<Hash>) —

Array of information hashes, one for each collection in the database.

Since:

2.0.5

[ GitHub ]

# File 'lib/mongo/database.rb', line 167


def list_collections(options = {})
  View.new(self).list_collections(options)
end

#read_command(operation, opts = {}) ⇒ `Hash`

This method is for internal use only.

Execute a read command on the database, retrying the read if necessary.

Parameters:

operation (Hash) —

The command to execute.
opts (Hash) (defaults to: {}) —

The command options.

Options Hash (opts):

:read (Hash) —

The read preference for this command.
:session (Session) —

The session to use for this command.

Returns:

(Hash) —

The result of the command execution.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 251


def read_command(operation, opts = {})
  txn_read_pref = if opts[:session] && opts[:session].in_transaction?
    opts[:session].txn_read_preference
  else
    nil
  end
  txn_read_pref ||= opts[:read] || ServerSelector::PRIMARY
  Lint.validate_underscore_read_preference(txn_read_pref)
  preference = ServerSelector.get(txn_read_pref)

  client.send(:with_session, opts) do |session|
    read_with_retry(session, preference) do |server|
      Operation::Command.new(
        selector: operation.dup,
        db_name: name,
        read: preference,
        session: session,
        comment: opts[:comment],
      ).execute(server, context: Operation::Context.new(client: client, session: session))
    end
  end
end

#users ⇒ `View::User`

Get the user view for this database.

Examples:

Get the user view.

database.users

Returns:

(View::User) —

The user view.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 370


def users
  Auth::User::View.new(self)
end

#watch(pipeline = [], options = {}) ⇒ `ChangeStream`

Note:

A change stream only allows ‘majority’ read concern.

Note:

This helper method is preferable to running a raw aggregation with a $changeStream stage, for the purpose of supporting resumability.

As of version 3.6 of the MongoDB server, a “$changeStream“ pipeline stage is supported in the aggregation framework. As of version 4.0, this stage allows users to request that notifications are sent for all changes that occur in the client’s database.

Examples:

Get change notifications for a given database..

database.watch([{ '$match' => { operationType: { '$in' => ['insert', 'replace'] } } }])

Parameters:

pipeline (Array<Hash>) (defaults to: []) —

Optional additional filter operators.
options (Hash) (defaults to: {}) —

The change stream options.

Options Hash (options):

:full_document (String) —

Allowed values: nil, ‘default’, ‘updateLookup’, ‘whenAvailable’, ‘required’.

The default is to not send a value (i.e. nil), which is equivalent to ‘default’. By default, the change notification for partial updates will include a delta describing the changes to the document.

When set to ‘updateLookup’, the change notification for partial updates will include both a delta describing the changes to the document as well as a copy of the entire document that was changed from some time after the change occurred.

When set to ‘whenAvailable’, configures the change stream to return the post-image of the modified document for replace and update change events if the post-image for this event is available.

When set to ‘required’, the same behavior as ‘whenAvailable’ except that an error is raised if the post-image is not available.
:full_document_before_change (String) —

Allowed values: nil, ‘whenAvailable’, ‘required’, ‘off’.

The default is to not send a value (i.e. nil), which is equivalent to ‘off’.

When set to ‘whenAvailable’, configures the change stream to return the pre-image of the modified document for replace, update, and delete change events if it is available.

When set to ‘required’, the same behavior as ‘whenAvailable’ except that an error is raised if the pre-image is not available.
:resume_after (BSON::Document, Hash) —

Specifies the logical starting point for the new change stream.
:max_await_time_ms (Integer) —

The maximum amount of time for the server to wait on new documents to satisfy a change stream query.
:batch_size (Integer) —

The number of documents to return per batch.
:collation (BSON::Document, Hash) —

The collation to use.
:session (Session) —

The session to use.
:start_at_operation_time (BSON::Timestamp) —

Only return changes that occurred after the specified timestamp. Any command run against the server will return a cluster time that can be used here. Only recognized by server versions 4.0+.
:comment (Object) —

A user-provided comment to attach to this command.
:show_expanded_events (Boolean) —

Enables the server to send the ‘expanded’ list of change stream events. The list of additional events included with this flag set are: createIndexes, dropIndexes, modify, create, shardCollection, reshardCollection, refineCollectionShardKey.

Returns:

(ChangeStream) —

The change stream object.

Since:

2.6.0

[ GitHub ]

# File 'lib/mongo/database.rb', line 472


def watch(pipeline = [], options = {})
  view_options = options.dup
  view_options[:await_data] = true if options[:max_await_time_ms]

  Mongo::Collection::View::ChangeStream.new(
    Mongo::Collection::View.new(collection("#{COMMAND}.aggregate"), {}, view_options),
    pipeline,
    Mongo::Collection::View::ChangeStream::DATABASE,
    options)
end

Class: Mongo::Database

Overview

Constant Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Retryable - Included

Constructor Details

.new(client, name, options = {}) ⇒ Database

Class Method Details

.create(client) ⇒ Database

Instance Attribute Details

#client ⇒ Client (readonly)

#name ⇒ String (readonly)

#options ⇒ Hash (readonly)

Instance Method Details

#==(other) ⇒ true, false

#[](collection_name, options = {}) ⇒ Mongo::Collection Also known as: #collection

#aggregate(pipeline, options = {}) ⇒ Collection::View::Aggregation

#cluster ⇒ Mongo::Server

#collection(collection_name, options = {})

#collection_names(options = {}) ⇒ Array<String>

#collections(options = {}) ⇒ Array<Mongo::Collection>

#command(operation, opts = {}) ⇒ Mongo::Operation::Result

#drop(options = {}) ⇒ Result

#fs(options = {}) ⇒ Grid::FSBucket

#inspect ⇒ String

#list_collections(options = {}) ⇒ Array<Hash>

#read_command(operation, opts = {}) ⇒ Hash

#users ⇒ View::User

#watch(pipeline = [], options = {}) ⇒ ChangeStream

`Retryable` - Included

.new(client, name, options = {}) ⇒ `Database`

.create(client) ⇒ `Database`

#name ⇒ `String` (readonly)

#options ⇒ `Hash` (readonly)

#==(other) ⇒ `true`, `false`

#collection_names(options = {}) ⇒ `Array`<`String`>

#collections(options = {}) ⇒ `Array`<Mongo::Collection>

#drop(options = {}) ⇒ `Result`

#inspect ⇒ `String`

#list_collections(options = {}) ⇒ `Array`<`Hash`>

#read_command(operation, opts = {}) ⇒ `Hash`

#users ⇒ `View::User`

#watch(pipeline = [], options = {}) ⇒ `ChangeStream`