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Mongoid::Criteria

The Criteria class is the core object needed in Mongoid to retrieve objects from the database. It is a DSL that essentially sets up the selector and options arguments that get passed on to a Mongo::Collection in the Ruby driver. Each method on the Criteria returns self to they can be chained in order to create a readable criterion to be executed against the database.

Attributes

embedded[RW]
klass[RW]

Public Class Methods

new(klass) click to toggle source

Initialize the new criteria.

@example Init the new criteria.

Criteria.new(Band)

@param [ Class ] klass The model class.

@since 1.0.0

# File lib/mongoid/criteria.rb, line 184
def initialize(klass)
  @klass = klass
  klass ? super(klass.aliased_fields, klass.fields) : super({}, {})
end

Public Instance Methods

==(other) click to toggle source

Returns true if the supplied Enumerable or Criteria is equal to the results of this Criteria or the criteria itself.

@note This will force a database load when called if an enumerable is passed.

@param [ Object ] other The other Enumerable or Criteria to compare to.

@return [ true, false ] If the objects are equal.

@since 1.0.0

# File lib/mongoid/criteria.rb, line 37
def ==(other)
  return super if other.respond_to?(:selector)
  entries == other
end
as_json(options = nil) click to toggle source

Needed to properly get a criteria back as json

@example Get the criteria as json.

Person.where(:title => "Sir").as_json

@param [ Hash ] options Options to pass through to the serializer.

@return [ String ] The JSON string.

# File lib/mongoid/criteria.rb, line 50
def as_json(options = nil)
  entries.as_json(options)
end
cache() click to toggle source

Tells the criteria that the cursor that gets returned needs to be cached. This is so multiple iterations don't hit the database multiple times, however this is not advisable when working with large data sets as the entire results will get stored in memory.

@example Flag the criteria as cached.

criteria.cache

@return [ Criteria ] The cloned criteria.

# File lib/mongoid/criteria.rb, line 63
def cache
  crit = clone
  crit.options.merge!(cache: true)
  crit
end
cached?() click to toggle source

Will return true if the cache option has been set.

@example Is the criteria cached?

criteria.cached?

@return [ true, false ] If the criteria is flagged as cached.

# File lib/mongoid/criteria.rb, line 75
def cached?
  options[:cache] == true
end
documents() click to toggle source

Get the documents from the embedded criteria.

@example Get the documents.

criteria.documents

@return [ Array<Document> ] The documents.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 87
def documents
  @documents ||= []
end
documents=(docs) click to toggle source

Set the embedded documents on the criteria.

@example Set the documents.

@param [ Array<Document> ] docs The embedded documents.

@return [ Array<Document> ] The embedded documents.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 100
def documents=(docs)
  @documents = docs
end
embedded?() click to toggle source

Is the criteria for embedded documents?

@example Is the criteria for embedded documents?

criteria.embedded?

@return [ true, false ] If the criteria is embedded.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 112
def embedded?
  !!@embedded
end
extract_id() click to toggle source

Extract a single id from the provided criteria. Could be in an $and query or a straight _id query.

@example Extract the id.

criteria.extract_id

@return [ Object ] The id.

@since 2.3.0

# File lib/mongoid/criteria.rb, line 125
def extract_id
  selector.extract_id
end
extras(extras) click to toggle source

Adds a criterion to the Criteria that specifies additional options to be passed to the Ruby driver, in the exact format for the driver.

@example Add extra params to the criteria. criteria.extras(:limit => 20, :skip => 40)

@param [ Hash ] extras The extra driver options.

@return [ Criteria ] The cloned criteria.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 140
def extras(extras)
  crit = clone
  crit.options.merge!(extras)
  crit
end
field_list() click to toggle source

Get the list of included fields.

@example Get the field list.

criteria.field_list

@return [ Array<String> ] The fields.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 154
def field_list
  if options[:fields]
    options[:fields].keys.reject{ |key| key == "_type" }
  else
    []
  end
end
for_js(javascript, scope = {}) click to toggle source

Find documents by the provided javascript and scope. Uses a $where but is different from +Criteria#where+ in that it will pass a code object to the query instead of a pure string. Safe against Javascript injection attacks.

@example Find by javascript.

Band.for_js("this.name = param", param: "Tool")

@param [ String ] javascript The javascript to execute in the $where. @param [ Hash ] scope The scope for the code.

@return [ Criteria ] The criteria.

@since 3.1.0

# File lib/mongoid/criteria.rb, line 440
def for_js(javascript, scope = {})
  js_query(Moped::BSON::Code.new(javascript, scope))
end
freeze() click to toggle source

When freezing a criteria we need to initialize the context first otherwise the setting of the context on attempted iteration will raise a runtime error.

@example Freeze the criteria.

criteria.freeze

@return [ Criteria ] The frozen criteria.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 172
def freeze
  context and inclusions and super
end
includes(*relations) click to toggle source

Eager loads all the provided relations. Will load all the documents into the identity map who's ids match based on the extra query for the ids.

@note This will only work if Mongoid's identity map is enabled. To do

so set identity_map_enabled: true in your mongoid.yml

@note This will work for embedded relations that reference another

collection via belongs_to as well.

@note Eager loading brings all the documents into memory, so there is a

sweet spot on the performance gains. Internal benchmarks show that
eager loading becomes slower around 100k documents, but this will
naturally depend on the specific application.

@example Eager load the provided relations.

Person.includes(:posts, :game)

@param [ Array<Symbol> ] relations The names of the relations to eager

load.

@return [ Criteria ] The cloned criteria.

@since 2.2.0

# File lib/mongoid/criteria.rb, line 213
def includes(*relations)
  relations.flatten.each do |name|
    metadata = klass.reflect_on_association(name)
    raise Errors::InvalidIncludes.new(klass, relations) unless metadata
    inclusions.push(metadata) unless inclusions.include?(metadata)
  end
  clone
end
inclusions() click to toggle source

Get a list of criteria that are to be executed for eager loading.

@example Get the eager loading inclusions.

Person.includes(:game).inclusions

@return [ Array<Metadata> ] The inclusions.

@since 2.2.0

# File lib/mongoid/criteria.rb, line 230
def inclusions
  @inclusions ||= []
end
inclusions=(value) click to toggle source

Set the inclusions for the criteria.

@example Set the inclusions.

criteria.inclusions = [ meta ]

@param [ Array<Metadata> ] The inclusions.

@return [ Array<Metadata> ] The new inclusions.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 244
def inclusions=(value)
  @inclusions = value
end
merge(other) click to toggle source
criteria.merge({
  klass: Band,
  where: { name: "Depeche Mode" },
  order_by: { name: 1 }
})

@param [ Criteria ] other The other criterion to merge with.

@return [ Criteria ] A cloned self.

# File lib/mongoid/criteria.rb, line 268
def merge(other)
  crit = clone
  crit.merge!(other)
  crit
end
merge!(other) click to toggle source

Merge the other criteria into this one.

@example Merge another criteria into this criteria.

criteria.merge(Person.where(name: "bob"))

@param [ Criteria ] other The criteria to merge in.

@return [ Criteria ] The merged criteria.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 284
def merge!(other)
  criteria = other.to_criteria
  selector.merge!(criteria.selector)
  options.merge!(criteria.options)
  self.documents = criteria.documents.dup unless criteria.documents.empty?
  self.scoping_options = criteria.scoping_options
  self.inclusions = (inclusions + criteria.inclusions.dup).uniq
  self
end
only(*args) click to toggle source

Overriden to include _type in the fields.

@example Limit the fields returned from the database.

Band.only(:name)

@param [ Array<Symbol> ] args The names of the fields.

@return [ Criteria ] The cloned criteria.

@since 1.0.0

# File lib/mongoid/criteria.rb, line 304
def only(*args)
  return clone if args.flatten.empty?
  args = args.flatten
  if klass.hereditary?
    super(*args.push(:_type))
  else
    super(*args)
  end
end
respond_to?(name, include_private = false) click to toggle source

Returns true if criteria responds to the given method.

@example Does the criteria respond to the method?

crtiteria.respond_to?(:each)

@param [ Symbol ] name The name of the class method on the Document. @param [ true, false ] include_private Whether to include privates.

@return [ true, false ] If the criteria responds to the method.

# File lib/mongoid/criteria.rb, line 323
def respond_to?(name, include_private = false)
  super || klass.respond_to?(name) || entries.respond_to?(name, include_private)
end
to_criteria() click to toggle source

Convenience for objects that want to be merged into a criteria.

@example Convert to a criteria.

criteria.to_criteria

@return [ Criteria ] self.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 337
def to_criteria
  self
end
to_proc() click to toggle source

Convert the criteria to a proc.

@example Convert the criteria to a proc.

criteria.to_proc

@return [ Proc ] The wrapped criteria.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 349
def to_proc
  ->{ self }
end
type(types) click to toggle source

Adds a criterion to the Criteria that specifies a type or an Array of types that must be matched.

@example Match only specific models.

criteria.type('Browser')
criteria.type(['Firefox', 'Browser'])

@param [ Array<String> ] types The types to match against.

@return [ Criteria ] The cloned criteria.

# File lib/mongoid/criteria.rb, line 363
def type(types)
  any_in(_type: Array(types))
end
where(expression) click to toggle source

This is the general entry point for most MongoDB queries. This either creates a standard field: value selection, and expanded selection with the use of hash methods, or a $where selection if a string is provided.

@example Add a standard selection.

criteria.where(name: "syd")

@example Add a javascript selection.

criteria.where("this.name == 'syd'")

@param [ String, Hash ] criterion The javascript or standard selection.

@raise [ UnsupportedJavascript ] If provided a string and the criteria

is embedded.

@return [ Criteria ] The cloned selectable.

@since 1.0.0

# File lib/mongoid/criteria.rb, line 385
def where(expression)
  if expression.is_a?(::String) && embedded?
    raise Errors::UnsupportedJavascript.new(klass, expression)
  end
  super
end
with(options) click to toggle source

Tell the next persistance operation to query from a specific collection, database or session.

@example Send the criteria to another collection.

Band.where(name: "Depeche Mode").with(collection: "artists")

@param [ Hash ] options The storage options.

@option options [ String, Symbol ] :collection The collection name. @option options [ String, Symbol ] :database The database name. @option options [ String, Symbol ] :session The session name.

@return [ Criteria ] The criteria.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 407
def with(options)
  Threaded.set_persistence_options(klass, options)
  self
end
without_options() click to toggle source

Get a version of this criteria without the options.

@example Get the criteria without options.

criteria.without_options

@return [ Criteria ] The cloned criteria.

@since 3.0.4

# File lib/mongoid/criteria.rb, line 420
def without_options
  crit = clone
  crit.options.clear
  crit
end

[Validate]

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