class Sequel::Model::Associations::AssociationReflection
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.
Constants
- ASSOCIATION_DATASET_PROC
- FINALIZE_SETTINGS
Map of methods to cache keys used for finalizing associations.
Public Instance Methods
Name symbol for the _add internal association method
# File lib/sequel/model/associations.rb 36 def _add_method 37 self[:_add_method] 38 end
Name symbol for the _remove_all internal association method
# File lib/sequel/model/associations.rb 41 def _remove_all_method 42 self[:_remove_all_method] 43 end
Name symbol for the _remove internal association method
# File lib/sequel/model/associations.rb 46 def _remove_method 47 self[:_remove_method] 48 end
Name symbol for the _setter association method
# File lib/sequel/model/associations.rb 51 def _setter_method 52 self[:_setter_method] 53 end
Name symbol for the add association method
# File lib/sequel/model/associations.rb 56 def add_method 57 self[:add_method] 58 end
Apply all non-instance specific changes to the given dataset and return it.
# File lib/sequel/model/associations.rb 84 def apply_dataset_changes(ds) 85 ds = ds.with_extend(AssociationDatasetMethods).clone(:association_reflection => self) 86 if exts = self[:reverse_extend] 87 ds = ds.with_extend(*exts) 88 end 89 ds = ds.select(*select) if select 90 if c = self[:conditions] 91 ds = (c.is_a?(Array) && !Sequel.condition_specifier?(c)) ? ds.where(*c) : ds.where(c) 92 end 93 ds = ds.order(*self[:order]) if self[:order] 94 ds = ds.limit(*self[:limit]) if self[:limit] 95 ds = ds.limit(1).skip_limit_check if limit_to_single_row? 96 ds = ds.eager(self[:eager]) if self[:eager] 97 ds = ds.distinct if self[:distinct] 98 ds 99 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 138 def apply_distinct_on_eager_limit_strategy(ds) 139 keys = predicate_key 140 ds.distinct(*keys).order_prepend(*keys) 141 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 103 def apply_eager_dataset_changes(ds) 104 ds = apply_dataset_changes(ds) 105 if block = self[:eager_block] 106 ds = block.call(ds) 107 end 108 ds 109 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 113 def apply_eager_graph_limit_strategy(strategy, ds) 114 case strategy 115 when :distinct_on 116 apply_distinct_on_eager_limit_strategy(ds.order_prepend(*self[:order])) 117 when :window_function 118 apply_window_function_eager_limit_strategy(ds.order_prepend(*self[:order])).select(*ds.columns) 119 else 120 ds 121 end 122 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 126 def apply_eager_limit_strategy(ds, strategy=eager_limit_strategy, limit_and_offset=limit_and_offset()) 127 case strategy 128 when :distinct_on 129 apply_distinct_on_eager_limit_strategy(ds) 130 when :window_function 131 apply_window_function_eager_limit_strategy(ds, limit_and_offset) 132 else 133 ds 134 end 135 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 165 def apply_ruby_eager_limit_strategy(rows, limit_and_offset = limit_and_offset()) 166 name = self[:name] 167 return unless range = slice_range(limit_and_offset) 168 if returns_array? 169 rows.each{|o| o.associations[name] = o.associations[name][range] || []} 170 else 171 offset = range.begin 172 rows.each{|o| o.associations[name] = o.associations[name][offset]} 173 end 174 end
Use a window function to limit the results of the eager loading dataset.
# File lib/sequel/model/associations.rb 144 def apply_window_function_eager_limit_strategy(ds, limit_and_offset=limit_and_offset()) 145 rn = ds.row_number_column 146 limit, offset = limit_and_offset 147 ds = ds.unordered.select_append{|o| o.row_number.function.over(:partition=>predicate_key, :order=>ds.opts[:order]).as(rn)}.from_self 148 ds = ds.order(rn) if ds.db.database_type == :mysql 149 ds = if !returns_array? 150 ds.where(rn => offset ? offset+1 : 1) 151 elsif offset 152 offset += 1 153 if limit 154 ds.where(rn => (offset...(offset+limit))) 155 else 156 ds.where{SQL::Identifier.new(rn) >= offset} 157 end 158 else 159 ds.where{SQL::Identifier.new(rn) <= limit} 160 end 161 end
Whether the associations cache should use an array when storing the associated records during eager loading.
# File lib/sequel/model/associations.rb 178 def assign_singular? 179 !returns_array? 180 end
The class associated to the current model class via this association
# File lib/sequel/model/associations.rb 66 def associated_class 67 cached_fetch(:class) do 68 begin 69 constantize(self[:class_name]) 70 rescue NameError => e 71 raise NameError, "#{e.message} (this happened when attempting to find the associated class for #{inspect})", e.backtrace 72 end 73 end 74 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 79 def associated_dataset 80 cached_fetch(:_dataset){apply_dataset_changes(_associated_dataset)} 81 end
Return an dataset that will load the appropriate associated objects for the given object using this association.
# File lib/sequel/model/associations.rb 215 def association_dataset_for(object) 216 condition = if can_have_associated_objects?(object) 217 predicate_keys.zip(predicate_key_values(object)) 218 else 219 false 220 end 221 222 associated_dataset.where(condition) 223 end
Proc used to create the association dataset method.
# File lib/sequel/model/associations.rb 227 def association_dataset_proc 228 ASSOCIATION_DATASET_PROC 229 end
Name symbol for association method, the same as the name of the association.
# File lib/sequel/model/associations.rb 61 def association_method 62 self[:name] 63 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 185 def can_have_associated_objects?(obj) 186 true 187 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 191 def cloneable?(ref) 192 ref[:type] == self[:type] 193 end
Name symbol for the dataset association method
# File lib/sequel/model/associations.rb 196 def dataset_method 197 self[:dataset_method] 198 end
Whether the dataset needs a primary key to function, true by default.
# File lib/sequel/model/associations.rb 201 def dataset_need_primary_key? 202 true 203 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 207 def delete_row_number_column(ds=associated_dataset) 208 if eager_limit_strategy == :window_function 209 ds.row_number_column 210 end 211 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 337 def eager_graph_lazy_dataset? 338 true 339 end
The eager_graph limit strategy to use for this dataset
# File lib/sequel/model/associations.rb 232 def eager_graph_limit_strategy(strategy) 233 if self[:limit] || !returns_array? 234 strategy = strategy[self[:name]] if strategy.is_a?(Hash) 235 case strategy 236 when true 237 true_eager_graph_limit_strategy 238 when Symbol 239 strategy 240 else 241 if returns_array? || offset 242 :ruby 243 end 244 end 245 end 246 end
The eager limit strategy to use for this dataset.
# File lib/sequel/model/associations.rb 249 def eager_limit_strategy 250 cached_fetch(:_eager_limit_strategy) do 251 if self[:limit] || !returns_array? 252 case s = cached_fetch(:eager_limit_strategy){default_eager_limit_strategy} 253 when true 254 true_eager_limit_strategy 255 else 256 s 257 end 258 end 259 end 260 end
Eager load the associated objects using the hash of eager options, yielding each row to the block.
# File lib/sequel/model/associations.rb 264 def eager_load_results(eo, &block) 265 rows = eo[:rows] 266 unless eo[:initialize_rows] == false 267 Sequel.synchronize_with(eo[:mutex]){initialize_association_cache(rows)} 268 end 269 if eo[:id_map] 270 ids = eo[:id_map].keys 271 return ids if ids.empty? 272 end 273 strategy = eager_limit_strategy 274 cascade = eo[:associations] 275 eager_limit = nil 276 277 if eo[:eager_block] || eo[:loader] == false 278 ds = eager_loading_dataset(eo) 279 280 strategy = ds.opts[:eager_limit_strategy] || strategy 281 282 eager_limit = 283 if el = ds.opts[:eager_limit] 284 raise Error, "The :eager_limit dataset option is not supported for associations returning a single record" unless returns_array? 285 strategy ||= true_eager_graph_limit_strategy 286 if el.is_a?(Array) 287 el 288 else 289 [el, nil] 290 end 291 else 292 limit_and_offset 293 end 294 295 strategy = true_eager_graph_limit_strategy if strategy == :union 296 # Correlated subqueries are not supported for regular eager loading 297 strategy = :ruby if strategy == :correlated_subquery 298 strategy = nil if strategy == :ruby && assign_singular? 299 objects = apply_eager_limit_strategy(ds, strategy, eager_limit).all 300 elsif strategy == :union 301 objects = [] 302 ds = associated_dataset 303 loader = union_eager_loader 304 joiner = " UNION ALL " 305 ids.each_slice(subqueries_per_union).each do |slice| 306 objects.concat(ds.with_sql(slice.map{|k| loader.sql(*k)}.join(joiner)).to_a) 307 end 308 ds = ds.eager(cascade) if cascade 309 ds.send(:post_load, objects) 310 else 311 loader = placeholder_eager_loader 312 loader = loader.with_dataset{|dataset| dataset.eager(cascade)} if cascade 313 objects = loader.all(ids) 314 end 315 316 Sequel.synchronize_with(eo[:mutex]){objects.each(&block)} 317 318 if strategy == :ruby 319 apply_ruby_eager_limit_strategy(rows, eager_limit || limit_and_offset) 320 end 321 end
The key to use for the key hash when eager loading
# File lib/sequel/model/associations.rb 324 def eager_loader_key 325 self[:eager_loader_key] 326 end
By default associations do not need to select a key in an associated table to eagerly load.
# File lib/sequel/model/associations.rb 330 def eager_loading_use_associated_key? 331 false 332 end
Whether additional conditions should be added when using the filter by associations support.
# File lib/sequel/model/associations.rb 343 def filter_by_associations_add_conditions? 344 self[:conditions] || self[:eager_block] || self[:limit] 345 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 351 def filter_by_associations_conditions_expression(obj) 352 ds = filter_by_associations_conditions_dataset.where(filter_by_associations_conditions_subquery_conditions(obj)) 353 {filter_by_associations_conditions_key=>ds} 354 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 359 def finalize 360 return unless cache = self[:cache] 361 362 finalizer = proc do |meth, key| 363 next if has_key?(key) 364 365 # Allow calling private methods to make sure caching is done appropriately 366 send(meth) 367 self[key] = cache.delete(key) if cache.has_key?(key) 368 end 369 370 finalize_settings.each(&finalizer) 371 372 unless self[:instance_specific] 373 finalizer.call(:associated_eager_dataset, :associated_eager_dataset) 374 finalizer.call(:filter_by_associations_conditions_dataset, :filter_by_associations_conditions_dataset) 375 end 376 377 nil 378 end
# File lib/sequel/model/associations.rb 390 def finalize_settings 391 FINALIZE_SETTINGS 392 end
Whether to handle silent modification failure when adding/removing associated records, false by default.
# File lib/sequel/model/associations.rb 396 def handle_silent_modification_failure? 397 false 398 end
Initialize the associations cache for the current association for the given objects.
# File lib/sequel/model/associations.rb 401 def initialize_association_cache(objects) 402 name = self[:name] 403 if assign_singular? 404 objects.each{|object| object.associations[name] = nil} 405 else 406 objects.each{|object| object.associations[name] = []} 407 end 408 end
Show which type of reflection this is, and a guess at what code was used to create the association.
# File lib/sequel/model/associations.rb 412 def inspect 413 o = self[:orig_opts].dup 414 o.delete(:class) 415 o.delete(:class_name) 416 o.delete(:block) unless o[:block] 417 o[:class] = self[:orig_class] if self[:orig_class] 418 419 "#<#{self.class} #{self[:model]}.#{self[:type]} #{self[:name].inspect}#{", #{o.inspect[1...-1]}" unless o.empty?}>" 420 end
The limit and offset for this association (returned as a two element array).
# File lib/sequel/model/associations.rb 423 def limit_and_offset 424 if (v = self[:limit]).is_a?(Array) 425 v 426 else 427 [v, nil] 428 end 429 end
Whether the associated object needs a primary key to be added/removed, false by default.
# File lib/sequel/model/associations.rb 433 def need_associated_primary_key? 434 false 435 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 439 def placeholder_loader 440 if use_placeholder_loader? 441 cached_fetch(:placeholder_loader) do 442 Sequel::Dataset::PlaceholderLiteralizer.loader(associated_dataset) do |pl, ds| 443 ds = ds.where(Sequel.&(*predicate_keys.map{|k| SQL::BooleanExpression.new(:'=', k, pl.arg)})) 444 if self[:block] 445 ds = self[:block].call(ds) 446 end 447 ds 448 end 449 end 450 end 451 end
The values that predicate_keys
should match for objects to be associated.
# File lib/sequel/model/associations.rb 459 def predicate_key_values(object) 460 predicate_key_methods.map{|k| object.get_column_value(k)} 461 end
The keys to use for loading of the regular dataset, as an array.
# File lib/sequel/model/associations.rb 454 def predicate_keys 455 cached_fetch(:predicate_keys){Array(predicate_key)} 456 end
Qualify col
with the given table name.
# File lib/sequel/model/associations.rb 464 def qualify(table, col) 465 transform(col) do |k| 466 case k 467 when Symbol, SQL::Identifier 468 SQL::QualifiedIdentifier.new(table, k) 469 else 470 Sequel::Qualifier.new(table).transform(k) 471 end 472 end 473 end
Qualify col with the associated model's table name.
# File lib/sequel/model/associations.rb 476 def qualify_assoc(col) 477 qualify(associated_class.table_name, col) 478 end
Qualify col with the current model's table name.
# File lib/sequel/model/associations.rb 481 def qualify_cur(col) 482 qualify(self[:model].table_name, col) 483 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 491 def reciprocal 492 cached_fetch(:reciprocal) do 493 possible_recips = [] 494 495 associated_class.all_association_reflections.each do |assoc_reflect| 496 if reciprocal_association?(assoc_reflect) 497 possible_recips << assoc_reflect 498 end 499 end 500 501 if possible_recips.length == 1 502 cached_set(:reciprocal_type, possible_recips.first[:type]) if ambiguous_reciprocal_type? 503 possible_recips.first[:name] 504 end 505 end 506 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 510 def reciprocal_array? 511 true 512 end
Name symbol for the remove_all_ association method
# File lib/sequel/model/associations.rb 515 def remove_all_method 516 self[:remove_all_method] 517 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 521 def remove_before_destroy? 522 true 523 end
Name symbol for the remove_ association method
# File lib/sequel/model/associations.rb 526 def remove_method 527 self[:remove_method] 528 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 531 def remove_should_check_existing? 532 false 533 end
Whether this association returns an array of objects instead of a single object, true by default.
# File lib/sequel/model/associations.rb 537 def returns_array? 538 true 539 end
The columns to select when loading the association.
# File lib/sequel/model/associations.rb 542 def select 543 self[:select] 544 end
Whether to set the reciprocal association to self when loading associated records, false by default.
# File lib/sequel/model/associations.rb 548 def set_reciprocal_to_self? 549 false 550 end
Name symbol for the setter association method
# File lib/sequel/model/associations.rb 553 def setter_method 554 self[:setter_method] 555 end
The range used for slicing when using the :ruby eager limit strategy.
# File lib/sequel/model/associations.rb 558 def slice_range(limit_and_offset = limit_and_offset()) 559 limit, offset = limit_and_offset 560 if limit || offset 561 (offset||0)..(limit ? (offset||0)+limit-1 : -1) 562 end 563 end
Private Instance Methods
The base dataset used for the association, before any order/conditions options have been applied.
# File lib/sequel/model/associations.rb 588 def _associated_dataset 589 associated_class.dataset 590 end
Whether for the reciprocal type for the given association cannot be known in advantage, false by default.
# File lib/sequel/model/associations.rb 594 def ambiguous_reciprocal_type? 595 false 596 end
Apply a distinct on eager limit strategy using IN with a subquery that uses DISTINCT ON to ensure only the first matching record for each key is included.
# File lib/sequel/model/associations.rb 614 def apply_filter_by_associations_distinct_on_limit_strategy(ds) 615 k = filter_by_associations_limit_key 616 ds.where(k=>apply_distinct_on_eager_limit_strategy(associated_eager_dataset.select(*k))) 617 end
Apply a limit strategy to the given dataset so that filter by associations works with a limited dataset.
# File lib/sequel/model/associations.rb 600 def apply_filter_by_associations_limit_strategy(ds) 601 case filter_by_associations_limit_strategy 602 when :distinct_on 603 apply_filter_by_associations_distinct_on_limit_strategy(ds) 604 when :window_function 605 apply_filter_by_associations_window_function_limit_strategy(ds) 606 else 607 ds 608 end 609 end
Apply a distinct on eager limit strategy using IN with a subquery that uses a filter on the row_number window function to ensure that only rows inside the limit are returned.
# File lib/sequel/model/associations.rb 622 def apply_filter_by_associations_window_function_limit_strategy(ds) 623 ds.where(filter_by_associations_limit_key=>apply_window_function_eager_limit_strategy(associated_eager_dataset.select(*filter_by_associations_limit_alias_key)).select(*filter_by_associations_limit_aliases)) 624 end
The associated_dataset
with the eager_block callback already applied.
# File lib/sequel/model/associations.rb 627 def associated_eager_dataset 628 cached_fetch(:associated_eager_dataset) do 629 ds = associated_dataset.unlimited 630 if block = self[:eager_block] 631 ds = block.call(ds) 632 end 633 ds 634 end 635 end
If the key exists in the reflection hash, return it. If the key doesn't exist and association reflections are uncached, then yield to get the value. If the key doesn't exist and association reflection are cached, check the cache and return the value if present, or yield to get the value, cache the value, and return it.
# File lib/sequel/model/associations.rb 571 def cached_fetch(key) 572 fetch(key) do 573 return yield unless h = self[:cache] 574 Sequel.synchronize{return h[key] if h.has_key?(key)} 575 value = yield 576 Sequel.synchronize{h[key] = value} 577 end 578 end
Cache the value at the given key if caching.
# File lib/sequel/model/associations.rb 581 def cached_set(key, value) 582 return unless h = self[:cache] 583 Sequel.synchronize{h[key] = value} 584 end
The default eager limit strategy to use for this association
# File lib/sequel/model/associations.rb 666 def default_eager_limit_strategy 667 self[:model].default_eager_limit_strategy || :ruby 668 end
The dataset to use for eager loading associated objects for multiple current objects, given the hash passed to the eager loader.
# File lib/sequel/model/associations.rb 639 def eager_loading_dataset(eo=OPTS) 640 ds = eo[:dataset] || associated_eager_dataset 641 if id_map = eo[:id_map] 642 ds = ds.where(eager_loading_predicate_condition(id_map.keys)) 643 end 644 if associations = eo[:associations] 645 ds = ds.eager(associations) 646 end 647 if block = eo[:eager_block] 648 orig_ds = ds 649 ds = block.call(ds) 650 end 651 if eager_loading_use_associated_key? 652 ds = if ds.opts[:eager_graph] && !orig_ds.opts[:eager_graph] 653 block.call(orig_ds.select_append(*associated_key_array)) 654 else 655 ds.select_append(*associated_key_array) 656 end 657 end 658 if self[:eager_graph] 659 raise(Error, "cannot eagerly load a #{self[:type]} association that uses :eager_graph") if eager_loading_use_associated_key? 660 ds = ds.eager_graph(self[:eager_graph]) 661 end 662 ds 663 end
The predicate condition to use for the eager_loader.
# File lib/sequel/model/associations.rb 671 def eager_loading_predicate_condition(keys) 672 {predicate_key=>keys} 673 end
Add conditions to the dataset to not include NULL values for the associated keys, and select those keys.
# File lib/sequel/model/associations.rb 677 def filter_by_associations_add_conditions_dataset_filter(ds) 678 k = filter_by_associations_conditions_associated_keys 679 ds.select(*k).where(Sequel.negate(k.zip([]))) 680 end
The base dataset to use for the filter by associations conditions subquery, regardless of the objects that are passed in as filter values.
# File lib/sequel/model/associations.rb 700 def filter_by_associations_conditions_dataset 701 cached_fetch(:filter_by_associations_conditions_dataset) do 702 ds = associated_eager_dataset.unordered 703 ds = filter_by_associations_add_conditions_dataset_filter(ds) 704 ds = apply_filter_by_associations_limit_strategy(ds) 705 ds 706 end 707 end
The conditions to add to the filter by associations conditions subquery to restrict it to to the object(s) that was used as the filter value.
# File lib/sequel/model/associations.rb 685 def filter_by_associations_conditions_subquery_conditions(obj) 686 key = qualify(associated_class.table_name, associated_class.primary_key) 687 case obj 688 when Array 689 {key=>obj.map(&:pk)} 690 when Sequel::Dataset 691 {key=>obj.select(*Array(qualify(associated_class.table_name, associated_class.primary_key)))} 692 else 693 Array(key).zip(Array(obj.pk)) 694 end 695 end
The strategy to use to filter by a limited association
# File lib/sequel/model/associations.rb 710 def filter_by_associations_limit_strategy 711 v = fetch(:filter_limit_strategy, self[:eager_limit_strategy]) 712 if v || self[:limit] || !returns_array? 713 case v ||= self[:model].default_eager_limit_strategy 714 when true, :union, :ruby 715 # Can't use a union or ruby-based strategy for filtering by associations, switch to default eager graph limit 716 # strategy. 717 true_eager_graph_limit_strategy 718 when Symbol 719 v 720 end 721 end 722 end
Whether to limit the associated dataset to a single row.
# File lib/sequel/model/associations.rb 725 def limit_to_single_row? 726 !returns_array? 727 end
Any offset to use for this association (or nil if there is no offset).
# File lib/sequel/model/associations.rb 730 def offset 731 limit_and_offset.last 732 end
A placeholder literalizer used to speed up eager loading.
# File lib/sequel/model/associations.rb 735 def placeholder_eager_loader 736 cached_fetch(:placeholder_eager_loader) do 737 Sequel::Dataset::PlaceholderLiteralizer.loader(associated_dataset) do |pl, ds| 738 apply_eager_limit_strategy(eager_loading_dataset.where(predicate_key=>pl.arg), eager_limit_strategy) 739 end 740 end 741 end
The reciprocal type as an array, should be overridden in reflection subclasses that have ambiguous reciprocal types.
# File lib/sequel/model/associations.rb 745 def possible_reciprocal_types 746 [reciprocal_type] 747 end
Whether the given association reflection is possible reciprocal association for the current association reflection.
# File lib/sequel/model/associations.rb 751 def reciprocal_association?(assoc_reflect) 752 possible_reciprocal_types.include?(assoc_reflect[:type]) && 753 (begin; assoc_reflect.associated_class; rescue NameError; end) == self[:model] && 754 assoc_reflect[:conditions].nil? && 755 assoc_reflect[:block].nil? 756 end
The number of subqueries to use in each union query, used to eagerly load limited associations. Defaults to 40, the optimal number depends on the latency between the database and the application.
# File lib/sequel/model/associations.rb 761 def subqueries_per_union 762 self[:subqueries_per_union] || 40 763 end
If s
is an array, map s
over the block. Otherwise, just call the block with s
.
# File lib/sequel/model/associations.rb 767 def transform(s, &block) 768 s.is_a?(Array) ? s.map(&block) : (yield s) 769 end
The eager_graph limit strategy used when true is given as the value, choosing the best strategy based on what the database supports.
# File lib/sequel/model/associations.rb 785 def true_eager_graph_limit_strategy 786 if associated_class.dataset.supports_window_functions? 787 :window_function 788 else 789 :ruby 790 end 791 end
What eager limit strategy should be used when true is given as the value, defaults to UNION as that is the fastest strategy if the appropriate keys are indexed.
# File lib/sequel/model/associations.rb 773 def true_eager_limit_strategy 774 if self[:eager_graph] || (offset && !associated_dataset.supports_offsets_in_correlated_subqueries?) 775 # An SQL-based approach won't work if you are also eager graphing, 776 # so use a ruby based approach in that case. 777 :ruby 778 else 779 :union 780 end 781 end
A placeholder literalizer used to speed up the creation of union queries when eager loading a limited association.
# File lib/sequel/model/associations.rb 795 def union_eager_loader 796 cached_fetch(:union_eager_loader) do 797 Sequel::Dataset::PlaceholderLiteralizer.loader(associated_dataset) do |pl, ds| 798 ds = self[:eager_block].call(ds) if self[:eager_block] 799 keys = predicate_keys 800 ds = ds.where(keys.map{pl.arg}.zip(keys)) 801 if eager_loading_use_associated_key? 802 ds = ds.select_append(*associated_key_array) 803 end 804 ds.from_self 805 end 806 end 807 end
Whether the placeholder loader can be used to load the association.
# File lib/sequel/model/associations.rb 810 def use_placeholder_loader? 811 self[:use_placeholder_loader] 812 end