class Mongo::Database
Represents a database on the db server and operations that can execute on it at this level.
@since 2.0.0
Constants
- ADMIN
The admin database name.
@since 2.0.0
- COMMAND
The “collection” that database commands operate against.
@since 2.0.0
- DATABASES
Databases constant.
@since 2.1.0
- DEFAULT_OPTIONS
The default database options.
@since 2.0.0
- NAME
Database name field constant.
@since 2.1.0
- NAMESPACES
The name of the collection that holds all the collection names.
@since 2.0.0
Attributes
@return [ Client ] client The database client.
@return [ String ] name The name of the database.
@return [ Hash ] options The options.
Public Class Methods
Create a database for the provided client, for use when we don't want the client's original database instance to be the same.
@api private
@example Create a database for the client.
Database.create(client)
@param [ Client ] client The client to create on.
@return [ Database ] The database.
@since 2.0.0
# File lib/mongo/database.rb, line 304 def self.create(client) database = Database.new(client, client.options[:database], client.options) client.instance_variable_set(:@database, database) end
Instantiate a new database object.
@example Instantiate the database.
Mongo::Database.new(client, :test)
@param [ Mongo::Client ] client The driver client. @param [ String, Symbol ] name The name of the database. @param [ Hash ] options The options.
@raise [ Mongo::Database::InvalidName ] If the name is nil.
@since 2.0.0
# File lib/mongo/database.rb, line 207 def initialize(client, name, options = {}) raise Error::InvalidDatabaseName.new unless name @client = client @name = name.to_s.freeze @options = options.freeze end
Public Instance Methods
Check equality of the database object against another. Will simply check if the names are the same.
@example Check database equality.
database == other
@param [ Object ] other The object to check against.
@return [ true, false ] If the objects are equal.
@since 2.0.0
# File lib/mongo/database.rb, line 87 def ==(other) return false unless other.is_a?(Database) name == other.name end
Get a collection in this database by the provided name.
@example Get a collection.
database[:users]
@param [ String, Symbol ] collection_name The name of the collection. @param [ Hash ] options The options to the collection.
@return [ Mongo::Collection ] The collection object.
@since 2.0.0
# File lib/mongo/database.rb, line 103 def [](collection_name, options = {}) Collection.new(self, collection_name, options) end
Get all the names of the non-system collections in the database.
@example Get the collection names.
database.collection_names
@return [ Array<String> ] The names of all non-system collections.
@since 2.0.0
# File lib/mongo/database.rb, line 116 def collection_names(options = {}) View.new(self).collection_names(options) end
Get all the collections that belong to this database.
@example Get all the collections.
database.collections
@return [ Array<Mongo::Collection> ] All the collections.
@since 2.0.0
# File lib/mongo/database.rb, line 140 def collections collection_names.map { |name| collection(name) } end
Execute a command on the database.
@example Execute a command.
database.command(:ismaster => 1)
@param [ Hash ] operation The command to execute. @param [ Hash ] opts The command options.
@option opts :read [ Hash ] The read preference for this command.
@return [ Hash ] The result of the command execution.
# File lib/mongo/database.rb, line 155 def command(operation, opts = {}) txn_read_pref = opts[:session] && opts[:session].in_transaction? && opts[:session].txn_read_preference Mongo::Lint.validate_underscore_read_preference(txn_read_pref) preference = ServerSelector.get(txn_read_pref || opts[:read] || ServerSelector::PRIMARY) server = preference.select_server(cluster) client.send(:with_session, opts) do |session| Operation::Command.new({ :selector => operation.dup, :db_name => name, :read => preference, :session => session }).execute(server) end end
Drop the database and all its associated information.
@example Drop the database.
database.drop
@param [ Hash ] options The options for the operation.
@option options [ Session ] :session The session to use for the operation.
@return [ Result ] The result of the command.
@since 2.0.0
# File lib/mongo/database.rb, line 183 def drop(options = {}) operation = { :dropDatabase => 1 } client.send(:with_session, options) do |session| Operation::DropDatabase.new({ selector: operation, db_name: name, write_concern: write_concern, session: session }).execute(next_primary) end end
Get the Grid “filesystem” for this database.
@example Get the GridFS.
database.fs
@return [ Grid::FSBucket ] The GridFS for the database.
@since 2.0.0
# File lib/mongo/database.rb, line 234 def fs(options = {}) Grid::FSBucket.new(self, options) end
Get a pretty printed string inspection for the database.
@example Inspect the database.
database.inspect
@return [ String ] The database inspection.
@since 2.0.0
# File lib/mongo/database.rb, line 222 def inspect "#<Mongo::Database:0x#{object_id} name=#{name}>" end
Get info on all the collections in the database.
@example Get info on each collection.
database.list_collections
@return [ Array<Hash> ] Info for each collection in the database.
@since 2.0.5
# File lib/mongo/database.rb, line 128 def list_collections View.new(self).list_collections end
Get the user view for this database.
@example Get the user view.
database.users
@return [ View::User ] The user view.
@since 2.0.0
# File lib/mongo/database.rb, line 246 def users Auth::User::View.new(self) end
As of version 3.6 of the MongoDB server, a “$changeStream“ pipeline stage is supported in the aggregation framework. As of version 4.0, this stage allows users to request that notifications are sent for all changes that occur in the client's database.
@example Get change notifications for a given database..
database.watch([{ '$match' => { operationType: { '$in' => ['insert', 'replace'] } } }])
@param [ Array<Hash> ] pipeline Optional additional filter operators. @param [ Hash ] options The change stream options.
@option options [ String ] :full_document Allowed values: 'default', 'updateLookup'.
Defaults to 'default'. 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.
@option options [ BSON::Document, Hash ] :resume_after Specifies the logical starting point
for the new change stream.
@option options [ Integer ] :max_await_time_ms The maximum amount of time for the server to
wait on new documents to satisfy a change stream query.
@option options [ Integer ] :batch_size The number of documents to return per batch. @option options [ BSON::Document, Hash ] :collation The collation to use. @option options [ Session ] :session The session to use. @option options [ BSON::Timestamp ] :start_at_operation_time 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+.
@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.
@return [ ChangeStream ] The change stream object.
@since 2.6.0
# File lib/mongo/database.rb, line 283 def watch(pipeline = [], options = {}) Mongo::Collection::View::ChangeStream.new( Mongo::Collection::View.new(collection("#{COMMAND}.aggregate")), pipeline, Mongo::Collection::View::ChangeStream::DATABASE, options) end