Class | Sequel::Model::Associations::AssociationReflection |
In: |
lib/sequel/model/associations.rb
|
Parent: | Hash |
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.
ASSOCIATION_DATASET_PROC | = | proc{|r| r.association_dataset_for(self)} | ||
FINALIZE_SETTINGS | = | { :associated_class=>:class, :associated_dataset=>:_dataset, :associated_eager_dataset=>:associated_eager_dataset, :eager_limit_strategy=>:_eager_limit_strategy, :filter_by_associations_conditions_dataset=>:filter_by_associations_conditions_dataset, :placeholder_loader=>:placeholder_loader, :predicate_key=>:predicate_key, :predicate_keys=>:predicate_keys, :reciprocal=>:reciprocal, }.freeze | 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 36 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, line 41 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, line 46 46: def _remove_method 47: self[:_remove_method] 48: end
Name symbol for the _setter association method
# File lib/sequel/model/associations.rb, line 51 51: def _setter_method 52: self[:_setter_method] 53: end
Name symbol for the add association method
# File lib/sequel/model/associations.rb, line 56 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, line 84 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, line 138 138: 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, line 103 103: 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, line 113 113: 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, line 126 126: 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, line 165 165: def apply_ruby_eager_limit_strategy(rows, limit_and_offset = limit_and_offset()) 166: name = self[:name] 167: if returns_array? 168: range = slice_range(limit_and_offset) 169: rows.each{|o| o.associations[name] = o.associations[name][range] || []} 170: elsif sr = slice_range(limit_and_offset) 171: offset = sr.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, line 144 144: 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, line 178 178: 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, line 66 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, line 79 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, line 215 215: 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, line 227 227: 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, line 61 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, line 185 185: 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, line 191 191: def cloneable?(ref) 192: ref[:type] == self[:type] 193: end
Name symbol for the dataset association method
# File lib/sequel/model/associations.rb, line 196 196: 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, line 201 201: 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, line 207 207: 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, line 334 334: def eager_graph_lazy_dataset? 335: true 336: end
The eager_graph limit strategy to use for this dataset
# File lib/sequel/model/associations.rb, line 232 232: 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, line 249 249: 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, line 264 264: def eager_load_results(eo, &block) 265: rows = eo[:rows] 266: initialize_association_cache(rows) unless eo[:initialize_rows] == false 267: if eo[:id_map] 268: ids = eo[:id_map].keys 269: return ids if ids.empty? 270: end 271: strategy = eager_limit_strategy 272: cascade = eo[:associations] 273: eager_limit = nil 274: 275: if eo[:eager_block] || eo[:loader] == false 276: ds = eager_loading_dataset(eo) 277: 278: strategy = ds.opts[:eager_limit_strategy] || strategy 279: 280: eager_limit = 281: if el = ds.opts[:eager_limit] 282: raise Error, "The :eager_limit dataset option is not supported for associations returning a single record" unless returns_array? 283: strategy ||= true_eager_graph_limit_strategy 284: if el.is_a?(Array) 285: el 286: else 287: [el, nil] 288: end 289: else 290: limit_and_offset 291: end 292: 293: strategy = true_eager_graph_limit_strategy if strategy == :union 294: # Correlated subqueries are not supported for regular eager loading 295: strategy = :ruby if strategy == :correlated_subquery 296: strategy = nil if strategy == :ruby && assign_singular? 297: objects = apply_eager_limit_strategy(ds, strategy, eager_limit).all 298: elsif strategy == :union 299: objects = [] 300: ds = associated_dataset 301: loader = union_eager_loader 302: joiner = " UNION ALL " 303: ids.each_slice(subqueries_per_union).each do |slice| 304: objects.concat(ds.with_sql(slice.map{|k| loader.sql(*k)}.join(joiner)).to_a) 305: end 306: ds = ds.eager(cascade) if cascade 307: ds.send(:post_load, objects) 308: else 309: loader = placeholder_eager_loader 310: loader = loader.with_dataset{|dataset| dataset.eager(cascade)} if cascade 311: objects = loader.all(ids) 312: end 313: 314: objects.each(&block) 315: if strategy == :ruby 316: apply_ruby_eager_limit_strategy(rows, eager_limit || limit_and_offset) 317: end 318: end
The key to use for the key hash when eager loading
# File lib/sequel/model/associations.rb, line 321 321: def eager_loader_key 322: self[:eager_loader_key] 323: end
Whether additional conditions should be added when using the filter by associations support.
# File lib/sequel/model/associations.rb, line 340 340: def filter_by_associations_add_conditions? 341: self[:conditions] || self[:eager_block] || self[:limit] 342: 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 348 348: def filter_by_associations_conditions_expression(obj) 349: ds = filter_by_associations_conditions_dataset.where(filter_by_associations_conditions_subquery_conditions(obj)) 350: {filter_by_associations_conditions_key=>ds} 351: 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 356 356: def finalize 357: return unless cache = self[:cache] 358: 359: finalize_settings.each do |meth, key| 360: next if has_key?(key) 361: 362: # Allow calling private methods to make sure caching is done appropriately 363: send(meth) 364: self[key] = cache.delete(key) if cache.has_key?(key) 365: end 366: 367: nil 368: end
# File lib/sequel/model/associations.rb, line 382 382: def finalize_settings 383: FINALIZE_SETTINGS 384: end
Whether to handle silent modification failure when adding/removing associated records, false by default.
# File lib/sequel/model/associations.rb, line 388 388: def handle_silent_modification_failure? 389: false 390: end
Initialize the associations cache for the current association for the given objects.
# File lib/sequel/model/associations.rb, line 393 393: def initialize_association_cache(objects) 394: name = self[:name] 395: if assign_singular? 396: objects.each{|object| object.associations[name] = nil} 397: else 398: objects.each{|object| object.associations[name] = []} 399: end 400: 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, line 404 404: def inspect 405: o = self[:orig_opts].dup 406: o.delete(:class) 407: o.delete(:class_name) 408: o.delete(:block) unless o[:block] 409: o[:class] = self[:orig_class] if self[:orig_class] 410: 411: "#<#{self.class} #{self[:model]}.#{self[:type]} #{self[:name].inspect}#{", #{o.inspect[1...-1]}" unless o.empty?}>" 412: end
The limit and offset for this association (returned as a two element array).
# File lib/sequel/model/associations.rb, line 415 415: def limit_and_offset 416: if (v = self[:limit]).is_a?(Array) 417: v 418: else 419: [v, nil] 420: end 421: end
Whether the associated object needs a primary key to be added/removed, false by default.
# File lib/sequel/model/associations.rb, line 425 425: def need_associated_primary_key? 426: false 427: 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 431 431: def placeholder_loader 432: if use_placeholder_loader? 433: cached_fetch(:placeholder_loader) do 434: Sequel::Dataset::PlaceholderLiteralizer.loader(associated_dataset) do |pl, ds| 435: ds.where(Sequel.&(*predicate_keys.map{|k| SQL::BooleanExpression.new('=''=', k, pl.arg)})) 436: end 437: end 438: end 439: end
The values that predicate_keys should match for objects to be associated.
# File lib/sequel/model/associations.rb, line 447 447: def predicate_key_values(object) 448: predicate_key_methods.map{|k| object.get_column_value(k)} 449: end
The keys to use for loading of the regular dataset, as an array.
# File lib/sequel/model/associations.rb, line 442 442: def predicate_keys 443: cached_fetch(:predicate_keys){Array(predicate_key)} 444: end
Qualify col with the given table name.
# File lib/sequel/model/associations.rb, line 452 452: def qualify(table, col) 453: transform(col) do |k| 454: case k 455: when Symbol, SQL::Identifier 456: SQL::QualifiedIdentifier.new(table, k) 457: else 458: Sequel::Qualifier.new(table).transform(k) 459: end 460: end 461: end
Qualify col with the associated model‘s table name.
# File lib/sequel/model/associations.rb, line 464 464: def qualify_assoc(col) 465: qualify(associated_class.table_name, col) 466: end
Qualify col with the current model‘s table name.
# File lib/sequel/model/associations.rb, line 469 469: def qualify_cur(col) 470: qualify(self[:model].table_name, col) 471: 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 479 479: def reciprocal 480: cached_fetch(:reciprocal) do 481: possible_recips = [] 482: 483: associated_class.all_association_reflections.each do |assoc_reflect| 484: if reciprocal_association?(assoc_reflect) 485: possible_recips << assoc_reflect 486: end 487: end 488: 489: if possible_recips.length == 1 490: cached_set(:reciprocal_type, possible_recips.first[:type]) if ambiguous_reciprocal_type? 491: possible_recips.first[:name] 492: end 493: end 494: 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 498 498: def reciprocal_array? 499: true 500: end
Name symbol for the remove_all_ association method
# File lib/sequel/model/associations.rb, line 503 503: def remove_all_method 504: self[:remove_all_method] 505: 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 509 509: def remove_before_destroy? 510: true 511: end
Name symbol for the remove_ association method
# File lib/sequel/model/associations.rb, line 514 514: def remove_method 515: self[:remove_method] 516: 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 519 519: def remove_should_check_existing? 520: false 521: end
Whether this association returns an array of objects instead of a single object, true by default.
# File lib/sequel/model/associations.rb, line 525 525: def returns_array? 526: true 527: end
Whether to set the reciprocal association to self when loading associated records, false by default.
# File lib/sequel/model/associations.rb, line 536 536: def set_reciprocal_to_self? 537: false 538: end
Name symbol for the setter association method
# File lib/sequel/model/associations.rb, line 541 541: def setter_method 542: self[:setter_method] 543: end
The range used for slicing when using the :ruby eager limit strategy.
# File lib/sequel/model/associations.rb, line 546 546: def slice_range(limit_and_offset = limit_and_offset()) 547: limit, offset = limit_and_offset 548: if limit || offset 549: (offset||0)..(limit ? (offset||0)+limit-1 : -1) 550: end 551: end