AssociationReflection is a Hash subclass that keeps information on Sequel::Model associations. It provides methods to reduce internal code duplication. It should not be instantiated by the user.
Map of methods to cache keys used for finalizing associations.
Name symbol for the _add internal association method
# File lib/sequel/model/associations.rb, line 35 def _add_method :"_add_#{singularize(self[:name])}" end
Name symbol for the _remove_all internal association method
# File lib/sequel/model/associations.rb, line 40 def _remove_all_method :"_remove_all_#{self[:name]}" end
Name symbol for the _remove internal association method
# File lib/sequel/model/associations.rb, line 45 def _remove_method :"_remove_#{singularize(self[:name])}" end
Name symbol for the _setter association method
# File lib/sequel/model/associations.rb, line 50 def _setter_method :"_#{self[:name]}=" end
Name symbol for the add association method
# File lib/sequel/model/associations.rb, line 55 def add_method :"add_#{singularize(self[:name])}" end
Apply all non-instance specific changes to the given dataset and return it.
# File lib/sequel/model/associations.rb, line 83 def apply_dataset_changes(ds) ds = ds.with_extend(AssociationDatasetMethods). clone(:association_reflection => self) self[:extend].each{|m| ds = ds.with_extend(m)} ds = ds.select(*select) if select if c = self[:conditions] ds = (c.is_a?(Array) && !Sequel.condition_specifier?(c)) ? ds.where(*c) : ds.where(c) end ds = ds.order(*self[:order]) if self[:order] ds = ds.limit(*self[:limit]) if self[:limit] ds = ds.limit(1).skip_limit_check if limit_to_single_row? ds = ds.eager(self[:eager]) if self[:eager] ds = ds.distinct if self[:distinct] ds end
Use DISTINCT ON and ORDER BY clauses to limit the results to the first record with matching keys.
# File lib/sequel/model/associations.rb, line 136 def apply_distinct_on_eager_limit_strategy(ds) keys = predicate_key ds.distinct(*keys).order_prepend(*keys) end
Apply all non-instance specific changes and the eager_block option to the given dataset and return it.
# File lib/sequel/model/associations.rb, line 101 def apply_eager_dataset_changes(ds) ds = apply_dataset_changes(ds) if block = self[:eager_block] ds = block.call(ds) end ds end
Apply the eager graph limit strategy to the dataset to graph into the current dataset, or return the dataset unmodified if no SQL limit strategy is needed.
# File lib/sequel/model/associations.rb, line 111 def apply_eager_graph_limit_strategy(strategy, ds) case strategy when :distinct_on apply_distinct_on_eager_limit_strategy(ds.order_prepend(*self[:order])) when :window_function apply_window_function_eager_limit_strategy(ds.order_prepend(*self[:order])).select(*ds.columns) else ds end end
Apply an eager limit strategy to the dataset, or return the dataset unmodified if it doesn’t need an eager limit strategy.
# File lib/sequel/model/associations.rb, line 124 def apply_eager_limit_strategy(ds, strategy=eager_limit_strategy, limit_and_offset=limit_and_offset()) case strategy when :distinct_on apply_distinct_on_eager_limit_strategy(ds) when :window_function apply_window_function_eager_limit_strategy(ds, limit_and_offset) else ds end end
If the ruby eager limit strategy is being used, slice the array using the slice range to return the object(s) at the correct offset/limit.
# File lib/sequel/model/associations.rb, line 162 def apply_ruby_eager_limit_strategy(rows, limit_and_offset = limit_and_offset()) name = self[:name] if returns_array? range = slice_range(limit_and_offset) rows.each{|o| o.associations[name] = o.associations[name][range] || []} elsif sr = slice_range(limit_and_offset) offset = sr.begin rows.each{|o| o.associations[name] = o.associations[name][offset]} end end
Use a window function to limit the results of the eager loading dataset.
# File lib/sequel/model/associations.rb, line 142 def apply_window_function_eager_limit_strategy(ds, limit_and_offset=limit_and_offset()) rn = ds.row_number_column limit, offset = limit_and_offset ds = ds.unordered.select_append{|o| o.row_number.function.over(:partition=>predicate_key, :order=>ds.opts[:order]).as(rn)}.from_self ds = if !returns_array? ds.where(rn => offset ? offset+1 : 1) elsif offset offset += 1 if limit ds.where(rn => (offset...(offset+limit))) else ds.where{SQL::Identifier.new(rn) >= offset} end else ds.where{SQL::Identifier.new(rn) <= limit} end end
Whether the associations cache should use an array when storing the associated records during eager loading.
# File lib/sequel/model/associations.rb, line 175 def assign_singular? !returns_array? end
The class associated to the current model class via this association
# File lib/sequel/model/associations.rb, line 65 def associated_class cached_fetch(:class) do begin constantize(self[:class_name]) rescue NameError => e raise NameError, "#{e.message} (this happened when attempting to find the associated class for #{inspect})", e.backtrace end end end
The dataset associated via this association, with the non-instance specific changes already applied. This will be a joined dataset if the association requires joining tables.
# File lib/sequel/model/associations.rb, line 78 def associated_dataset cached_fetch(:_dataset){apply_dataset_changes(_associated_dataset)} end
Return an dataset that will load the appropriate associated objects for the given object using this association.
# File lib/sequel/model/associations.rb, line 212 def association_dataset_for(object) condition = if can_have_associated_objects?(object) predicate_keys.zip(predicate_key_values(object)) else false end associated_dataset.where(condition) end
Proc used to create the association dataset method.
# File lib/sequel/model/associations.rb, line 224 def association_dataset_proc ASSOCIATION_DATASET_PROC end
Name symbol for association method, the same as the name of the association.
# File lib/sequel/model/associations.rb, line 60 def association_method self[:name] end
Whether this association can have associated objects, given the current object. Should be false if obj cannot have associated objects because the necessary key columns are NULL.
# File lib/sequel/model/associations.rb, line 182 def can_have_associated_objects?(obj) true end
Whether you are able to clone from the given association type to the current association type, true by default only if the types match.
# File lib/sequel/model/associations.rb, line 188 def cloneable?(ref) ref[:type] == self[:type] end
Name symbol for the dataset association method
# File lib/sequel/model/associations.rb, line 193 def dataset_method :"#{self[:name]}_dataset" end
Whether the dataset needs a primary key to function, true by default.
# File lib/sequel/model/associations.rb, line 198 def dataset_need_primary_key? true end
Return the symbol used for the row number column if the window function eager limit strategy is being used, or nil otherwise.
# File lib/sequel/model/associations.rb, line 204 def delete_row_number_column(ds=associated_dataset) if eager_limit_strategy == :window_function ds.row_number_column end end
Whether to eagerly graph a lazy dataset, true by default. If this is false, the association won’t respect the :eager_graph option when loading the association for a single record.
# File lib/sequel/model/associations.rb, line 336 def eager_graph_lazy_dataset? true end
The eager_graph limit strategy to use for this dataset
# File lib/sequel/model/associations.rb, line 229 def eager_graph_limit_strategy(strategy) if self[:limit] || !returns_array? strategy = strategy[self[:name]] if strategy.is_a?(Hash) case strategy when true true_eager_graph_limit_strategy when Symbol strategy else if returns_array? || offset :ruby end end end end
The eager limit strategy to use for this dataset.
# File lib/sequel/model/associations.rb, line 246 def eager_limit_strategy cached_fetch(:_eager_limit_strategy) do if self[:limit] || !returns_array? case s = cached_fetch(:eager_limit_strategy){default_eager_limit_strategy} when true true_eager_limit_strategy else s end end end end
Eager load the associated objects using the hash of eager options, yielding each row to the block.
# File lib/sequel/model/associations.rb, line 261 def eager_load_results(eo, &block) rows = eo[:rows] initialize_association_cache(rows) unless eo[:initialize_rows] == false if eo[:id_map] ids = eo[:id_map].keys return ids if ids.empty? end strategy = eager_limit_strategy cascade = eo[:associations] eager_limit = nil if eo[:eager_block] || eo[:loader] == false ds = eager_loading_dataset(eo) strategy = ds.opts[:eager_limit_strategy] || strategy eager_limit = if el = ds.opts[:eager_limit] raise Error, "The :eager_limit dataset option is not supported for associations returning a single record" unless returns_array? strategy ||= true_eager_graph_limit_strategy if el.is_a?(Array) el else [el, nil] end else limit_and_offset end strategy = true_eager_graph_limit_strategy if strategy == :union # Correlated subqueries are not supported for regular eager loading strategy = :ruby if strategy == :correlated_subquery strategy = nil if strategy == :ruby && assign_singular? objects = apply_eager_limit_strategy(ds, strategy, eager_limit).all elsif strategy == :union objects = [] ds = associated_dataset loader = union_eager_loader joiner = " UNION ALL " ids.each_slice(subqueries_per_union).each do |slice| objects.concat(ds.with_sql(slice.map{|k| loader.sql(*k)}.join(joiner)).to_a) end ds = ds.eager(cascade) if cascade ds.send(:post_load, objects) else loader = placeholder_eager_loader loader = loader.with_dataset{|dataset| dataset.eager(cascade)} if cascade objects = loader.all(ids) end objects.each(&block) if strategy == :ruby apply_ruby_eager_limit_strategy(rows, eager_limit || limit_and_offset) end end
The key to use for the key hash when eager loading
# File lib/sequel/model/associations.rb, line 318 def eager_loader_key self[:eager_loader_key] end
Alias of predicate_key, only for backwards compatibility.
# File lib/sequel/model/associations.rb, line 329 def eager_loading_predicate_key predicate_key end
By default associations do not need to select a key in an associated table to eagerly load.
# File lib/sequel/model/associations.rb, line 324 def eager_loading_use_associated_key? false end
Whether additional conditions should be added when using the filter by associations support.
# File lib/sequel/model/associations.rb, line 342 def filter_by_associations_add_conditions? self[:conditions] || self[:eager_block] || self[:limit] end
The expression to use for the additional conditions to be added for the filter by association support, when the association itself is filtered. Works by using a subquery to test that the objects passed also meet the association filter criteria.
# File lib/sequel/model/associations.rb, line 350 def filter_by_associations_conditions_expression(obj) ds = filter_by_associations_conditions_dataset.where(filter_by_associations_conditions_subquery_conditions(obj)) {filter_by_associations_conditions_key=>ds} end
Finalize the association by first attempting to populate the thread-safe cache, and then transfering the thread-safe cache value to the association itself, so that a mutex is not needed to get the value.
# File lib/sequel/model/associations.rb, line 358 def finalize return unless cache = self[:cache] finalize_settings.each do |meth, key| next if has_key?(key) send(meth) self[key] = cache.delete(key) if cache.has_key?(key) end nil end
# File lib/sequel/model/associations.rb, line 383 def finalize_settings FINALIZE_SETTINGS end
Whether to handle silent modification failure when adding/removing associated records, false by default.
# File lib/sequel/model/associations.rb, line 389 def handle_silent_modification_failure? false end
Initialize the associations cache for the current association for the given objects.
# File lib/sequel/model/associations.rb, line 394 def initialize_association_cache(objects) name = self[:name] if assign_singular? objects.each{|object| object.associations[name] = nil} else objects.each{|object| object.associations[name] = []} end end
Show which type of reflection this is, and a guess at what line was used to create the association.
# File lib/sequel/model/associations.rb, line 405 def inspect o = self[:orig_opts].dup o.delete(:class) o.delete(:class_name) o.delete(:block) unless o[:block] o[:class] = self[:orig_class] if self[:orig_class] "#<#{self.class} #{self[:model]}.#{self[:type]} #{self[:name].inspect}#{", #{o.inspect[1...-1]}" unless o.empty?}>" end
The limit and offset for this association (returned as a two element array).
# File lib/sequel/model/associations.rb, line 416 def limit_and_offset if (v = self[:limit]).is_a?(Array) v else [v, nil] end end
Whether the associated object needs a primary key to be added/removed, false by default.
# File lib/sequel/model/associations.rb, line 426 def need_associated_primary_key? false end
A placeholder literalizer that can be used to lazily load the association. If one can’t be used, returns nil.
# File lib/sequel/model/associations.rb, line 432 def placeholder_loader if use_placeholder_loader? cached_fetch(:placeholder_loader) do Sequel::Dataset::PlaceholderLiteralizer.loader(associated_dataset) do |pl, ds| ds.where(Sequel.&(*predicate_keys.map{|k| SQL::BooleanExpression.new(:'=', k, pl.arg)})) end end end end
The values that #predicate_keys should match for objects to be associated.
# File lib/sequel/model/associations.rb, line 448 def predicate_key_values(object) predicate_key_methods.map{|k| object.get_column_value(k)} end
The keys to use for loading of the regular dataset, as an array.
# File lib/sequel/model/associations.rb, line 443 def predicate_keys cached_fetch(:predicate_keys){Array(predicate_key)} end
Qualify col
with the given table name. If col
is
an array of columns, return an array of qualified columns. Only qualifies
Symbols and SQL::Identifier values,
other values are not modified.
# File lib/sequel/model/associations.rb, line 455 def qualify(table, col) transform(col) do |k| case k when Symbol, SQL::Identifier SQL::QualifiedIdentifier.new(table, k) else Sequel::Qualifier.new(table).transform(k) end end end
Qualify col with the associated model’s table name.
# File lib/sequel/model/associations.rb, line 467 def qualify_assoc(col) qualify(associated_class.table_name, col) end
Qualify col with the current model’s table name.
# File lib/sequel/model/associations.rb, line 472 def qualify_cur(col) qualify(self[:model].table_name, col) end
Returns the reciprocal association variable, if one exists. The reciprocal association is the association in the associated class that is the opposite of the current association. For example, Album.many_to_one :artist and Artist.one_to_many :albums are reciprocal associations. This information is to populate reciprocal associations. For example, when you do this_artist.add_album(album) it sets album.artist to this_artist.
# File lib/sequel/model/associations.rb, line 482 def reciprocal cached_fetch(:reciprocal) do possible_recips = [] associated_class.all_association_reflections.each do |assoc_reflect| if reciprocal_association?(assoc_reflect) possible_recips << assoc_reflect end end if possible_recips.length == 1 cached_set(:reciprocal_type, possible_recips.first[:type]) if ambiguous_reciprocal_type? possible_recips.first[:name] end end end
Whether the reciprocal of this association returns an array of objects instead of a single object, true by default.
# File lib/sequel/model/associations.rb, line 501 def reciprocal_array? true end
Name symbol for the remove_all_ association method
# File lib/sequel/model/associations.rb, line 506 def remove_all_method :"remove_all_#{self[:name]}" end
Whether associated objects need to be removed from the association before being destroyed in order to preserve referential integrity.
# File lib/sequel/model/associations.rb, line 512 def remove_before_destroy? true end
Name symbol for the remove_ association method
# File lib/sequel/model/associations.rb, line 517 def remove_method :"remove_#{singularize(self[:name])}" end
Whether to check that an object to be disassociated is already associated to this object, false by default.
# File lib/sequel/model/associations.rb, line 522 def remove_should_check_existing? false end
Whether this association returns an array of objects instead of a single object, true by default.
# File lib/sequel/model/associations.rb, line 528 def returns_array? true end
The columns to select when loading the association.
# File lib/sequel/model/associations.rb, line 533 def select self[:select] end
Whether to set the reciprocal association to self when loading associated records, false by default.
# File lib/sequel/model/associations.rb, line 539 def set_reciprocal_to_self? false end
Name symbol for the setter association method
# File lib/sequel/model/associations.rb, line 544 def setter_method :"#{self[:name]}=" end
The range used for slicing when using the :ruby eager limit strategy.
# File lib/sequel/model/associations.rb, line 549 def slice_range(limit_and_offset = limit_and_offset()) limit, offset = limit_and_offset if limit || offset (offset||0)..(limit ? (offset||0)+limit-1 : -1) end end