Class: Sequel::Model::Associations::AssociationReflection

Inherits:
Hash
  • Object
show all
Includes:
Inflections
Defined in:
lib/sequel/model/associations.rb

Overview

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.

Constant Summary collapse

ASSOCIATION_DATASET_PROC = 
proc{|r| r.association_dataset_for(self)}

Constants included from Inflections

Inflections::CAMELIZE_CONVERT_REGEXP, Inflections::CAMELIZE_MODULE_REGEXP, Inflections::DASH, Inflections::DEMODULIZE_CONVERT_REGEXP, Inflections::EMPTY_STRING, Inflections::SLASH, Inflections::UNDERSCORE, Inflections::UNDERSCORE_CONVERT_REGEXP1, Inflections::UNDERSCORE_CONVERT_REGEXP2, Inflections::UNDERSCORE_CONVERT_REPLACE, Inflections::UNDERSCORE_MODULE_REGEXP, Inflections::VALID_CONSTANT_NAME_REGEXP

Instance Method Summary collapse

Methods included from Inflections

clear, irregular, plural, singular, uncountable

Methods inherited from Hash

#&, #case, #hstore, #pg_json, #pg_jsonb, #sql_expr, #sql_negate, #sql_or, #|, #~

Instance Method Details

#_add_method ⇒ Object

Name symbol for the _add internal association method



28
29
30
 
# File 'lib/sequel/model/associations.rb', line 28

def _add_method
  :"_add_#{singularize(self[:name])}"
end

#_remove_all_method ⇒ Object

Name symbol for the _remove_all internal association method



33
34
35
 
# File 'lib/sequel/model/associations.rb', line 33

def _remove_all_method
  :"_remove_all_#{self[:name]}"
end

#_remove_method ⇒ Object

Name symbol for the _remove internal association method



38
39
40
 
# File 'lib/sequel/model/associations.rb', line 38

def _remove_method
  :"_remove_#{singularize(self[:name])}"
end

#_setter_method ⇒ Object

Name symbol for the _setter association method



43
44
45
 
# File 'lib/sequel/model/associations.rb', line 43

def _setter_method
  :"_#{self[:name]}="
end

#add_method ⇒ Object

Name symbol for the add association method



48
49
50
 
# File 'lib/sequel/model/associations.rb', line 48

def add_method
  :"add_#{singularize(self[:name])}"
end

#apply_dataset_changes(ds) ⇒ Object

Apply all non-instance specific changes to the given dataset and return it.



70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
 
# File 'lib/sequel/model/associations.rb', line 70

def apply_dataset_changes(ds)
  ds.extend(AssociationDatasetMethods)
  ds.association_reflection = self
  self[:extend].each{|m| ds.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) if limit_to_single_row?
  ds = ds.eager(self[:eager]) if self[:eager]
  ds = ds.distinct if self[:distinct]
  ds
end

#apply_distinct_on_eager_limit_strategy(ds) ⇒ Object

Use DISTINCT ON and ORDER BY clauses to limit the results to the first record with matching keys.



123
124
125
126
 
# File 'lib/sequel/model/associations.rb', line 123

def apply_distinct_on_eager_limit_strategy(ds)
  keys = predicate_key
  ds.distinct(*keys).order_prepend(*keys)
end

#apply_eager_dataset_changes(ds) ⇒ Object

Apply all non-instance specific changes and the eager_block option to the given dataset and return it.



88
89
90
91
92
93
94
 
# File 'lib/sequel/model/associations.rb', line 88

def apply_eager_dataset_changes(ds)
  ds = apply_dataset_changes(ds)
  if block = self[:eager_block]
    ds = block.call(ds)
  end
  ds
end

#apply_eager_graph_limit_strategy(strategy, ds) ⇒ Object

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.



98
99
100
101
102
103
104
105
106
107
 
# File 'lib/sequel/model/associations.rb', line 98

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_eager_limit_strategy(ds, strategy = eager_limit_strategy, limit_and_offset = limit_and_offset()) ⇒ Object

Apply an eager limit strategy to the dataset, or return the dataset unmodified if it doesn’t need an eager limit strategy.



111
112
113
114
115
116
117
118
119
120
 
# File 'lib/sequel/model/associations.rb', line 111

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

#apply_ruby_eager_limit_strategy(rows, limit_and_offset = limit_and_offset()) ⇒ Object

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.



149
150
151
152
153
154
155
156
157
158
 
# File 'lib/sequel/model/associations.rb', line 149

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

#apply_window_function_eager_limit_strategy(ds, limit_and_offset = limit_and_offset()) ⇒ Object

Use a window function to limit the results of the eager loading dataset.



129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
 
# File 'lib/sequel/model/associations.rb', line 129

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{}.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

#assign_singular? ⇒ Boolean

Whether the associations cache should use an array when storing the associated records during eager loading.

Returns:

  • (Boolean) 


162
163
164
 
# File 'lib/sequel/model/associations.rb', line 162

def assign_singular?
  !returns_array?
end

#associated_class ⇒ Object

The class associated to the current model class via this association



58
59
60
 
# File 'lib/sequel/model/associations.rb', line 58

def associated_class
  cached_fetch(:class){constantize(self[:class_name])}
end

#associated_dataset ⇒ Object

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.



65
66
67
 
# File 'lib/sequel/model/associations.rb', line 65

def associated_dataset
  cached_fetch(:_dataset){apply_dataset_changes(_associated_dataset)}
end

#association_dataset_for(object) ⇒ Object

Return an dataset that will load the appropriate associated objects for the given object using this association.



199
200
201
 
# File 'lib/sequel/model/associations.rb', line 199

def association_dataset_for(object)
  associated_dataset.where(predicate_keys.zip(predicate_key_values(object)))
end

#association_dataset_proc ⇒ Object

Proc used to create the association dataset method.



205
206
207
 
# File 'lib/sequel/model/associations.rb', line 205

def association_dataset_proc
  ASSOCIATION_DATASET_PROC
end

#association_method ⇒ Object

Name symbol for association method, the same as the name of the association.



53
54
55
 
# File 'lib/sequel/model/associations.rb', line 53

def association_method
  self[:name]
end

#can_have_associated_objects?(obj) ⇒ Boolean

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.

Returns:

  • (Boolean) 


169
170
171
 
# File 'lib/sequel/model/associations.rb', line 169

def can_have_associated_objects?(obj)
  true
end

#cloneable?(ref) ⇒ Boolean

Whether you are able to clone from the given association type to the current association type, true by default only if the types match.

Returns:

  • (Boolean) 


175
176
177
 
# File 'lib/sequel/model/associations.rb', line 175

def cloneable?(ref)
  ref[:type] == self[:type]
end

#dataset_method ⇒ Object

Name symbol for the dataset association method



180
181
182
 
# File 'lib/sequel/model/associations.rb', line 180

def dataset_method
  :"#{self[:name]}_dataset"
end

#dataset_need_primary_key? ⇒ Boolean

Whether the dataset needs a primary key to function, true by default.

Returns:

  • (Boolean) 


185
186
187
 
# File 'lib/sequel/model/associations.rb', line 185

def dataset_need_primary_key?
  true
end

#delete_row_number_column(ds = associated_dataset) ⇒ Object

Return the symbol used for the row number column if the window function eager limit strategy is being used, or nil otherwise.



191
192
193
194
195
 
# File 'lib/sequel/model/associations.rb', line 191

def delete_row_number_column(ds=associated_dataset)
  if eager_limit_strategy == :window_function
    ds.row_number_column 
  end
end

#eager_graph_lazy_dataset? ⇒ Boolean

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.

Returns:

  • (Boolean) 


315
316
317
 
# File 'lib/sequel/model/associations.rb', line 315

def eager_graph_lazy_dataset?
  true
end

#eager_graph_limit_strategy(strategy) ⇒ Object

The eager_graph limit strategy to use for this dataset



210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
 
# File 'lib/sequel/model/associations.rb', line 210

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

#eager_limit_strategy ⇒ Object

The eager limit strategy to use for this dataset.



227
228
229
230
231
232
233
234
235
236
237
238
 
# File 'lib/sequel/model/associations.rb', line 227

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_results(eo, &block) ⇒ Object

Eager load the associated objects using the hash of eager options, yielding each row to the block.



242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
 
# File 'lib/sequel/model/associations.rb', line 242

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]
        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
    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

#eager_loader_key ⇒ Object

The key to use for the key hash when eager loading



297
298
299
 
# File 'lib/sequel/model/associations.rb', line 297

def eager_loader_key
  self[:eager_loader_key]
end

#eager_loading_predicate_key ⇒ Object

Alias of predicate_key, only for backwards compatibility.



308
309
310
 
# File 'lib/sequel/model/associations.rb', line 308

def eager_loading_predicate_key
  predicate_key
end

#eager_loading_use_associated_key? ⇒ Boolean

By default associations do not need to select a key in an associated table to eagerly load.

Returns:

  • (Boolean) 


303
304
305
 
# File 'lib/sequel/model/associations.rb', line 303

def eager_loading_use_associated_key?
  false
end

#filter_by_associations_add_conditions? ⇒ Boolean

Whether additional conditions should be added when using the filter by associations support.

Returns:

  • (Boolean) 


321
322
323
 
# File 'lib/sequel/model/associations.rb', line 321

def filter_by_associations_add_conditions?
  self[:conditions] || self[:eager_block] || self[:limit]
end

#filter_by_associations_conditions_expression(obj) ⇒ Object

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.



329
330
331
332
 
# File 'lib/sequel/model/associations.rb', line 329

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

#handle_silent_modification_failure? ⇒ Boolean

Whether to handle silent modification failure when adding/removing associated records, false by default.

Returns:

  • (Boolean) 


336
337
338
 
# File 'lib/sequel/model/associations.rb', line 336

def handle_silent_modification_failure?
  false
end

#initialize_association_cache(objects) ⇒ Object

Initialize the associations cache for the current association for the given objects.



341
342
343
344
345
346
347
348
 
# File 'lib/sequel/model/associations.rb', line 341

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

#limit_and_offset ⇒ Object

The limit and offset for this association (returned as a two element array).



351
352
353
354
355
356
357
 
# File 'lib/sequel/model/associations.rb', line 351

def limit_and_offset
  if (v = self[:limit]).is_a?(Array)
    v
  else
    [v, nil]
  end
end

#need_associated_primary_key? ⇒ Boolean

Whether the associated object needs a primary key to be added/removed, false by default.

Returns:

  • (Boolean) 


361
362
363
 
# File 'lib/sequel/model/associations.rb', line 361

def need_associated_primary_key?
  false
end

#placeholder_loader ⇒ Object

A placeholder literalizer that can be used to lazily load the association. If one can’t be used, returns nil.



367
368
369
370
371
372
373
374
375
 
# File 'lib/sequel/model/associations.rb', line 367

def placeholder_loader
  if use_placeholder_loader?
    cached_fetch(:placeholder_loader) do
      Sequel::Dataset::PlaceholderLiteralizer.loader(associated_dataset) do |pl, ds|
        ds.where(*predicate_keys.map{|k| SQL::BooleanExpression.new(:'=', k, pl.arg)})
      end
    end
  end
end

#predicate_key_values(object) ⇒ Object

The values that predicate_keys should match for objects to be associated.



383
384
385
 
# File 'lib/sequel/model/associations.rb', line 383

def predicate_key_values(object)
  predicate_key_methods.map{|k| object.get_column_value(k)}
end

#predicate_keys ⇒ Object

The keys to use for loading of the regular dataset, as an array.



378
379
380
 
# File 'lib/sequel/model/associations.rb', line 378

def predicate_keys
  cached_fetch(:predicate_keys){Array(predicate_key)}
end

#qualify(table, col) ⇒ Object

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.



390
391
392
393
394
395
396
397
398
399
 
# File 'lib/sequel/model/associations.rb', line 390

def qualify(table, col)
  transform(col) do |k|
    case k
    when Symbol, SQL::Identifier
      SQL::QualifiedIdentifier.new(table, k)
    else
      Sequel::Qualifier.new(self[:model].dataset, table).transform(k)
    end
  end
end

#qualify_assoc(col) ⇒ Object

Qualify col with the associated model’s table name.



402
403
404
 
# File 'lib/sequel/model/associations.rb', line 402

def qualify_assoc(col)
  qualify(associated_class.table_name, col)
end

#qualify_cur(col) ⇒ Object

Qualify col with the current model’s table name.



407
408
409
 
# File 'lib/sequel/model/associations.rb', line 407

def qualify_cur(col)
  qualify(self[:model].table_name, col)
end

#reciprocal ⇒ Object

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.



417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
 
# File 'lib/sequel/model/associations.rb', line 417

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

#reciprocal_array? ⇒ Boolean

Whether the reciprocal of this association returns an array of objects instead of a single object, true by default.

Returns:

  • (Boolean) 


436
437
438
 
# File 'lib/sequel/model/associations.rb', line 436

def reciprocal_array?
  true
end

#remove_all_method ⇒ Object

Name symbol for the remove_all_ association method



441
442
443
 
# File 'lib/sequel/model/associations.rb', line 441

def remove_all_method
  :"remove_all_#{self[:name]}"
end

#remove_before_destroy? ⇒ Boolean

Whether associated objects need to be removed from the association before being destroyed in order to preserve referential integrity.

Returns:

  • (Boolean) 


447
448
449
 
# File 'lib/sequel/model/associations.rb', line 447

def remove_before_destroy?
  true
end

#remove_method ⇒ Object

Name symbol for the remove_ association method



452
453
454
 
# File 'lib/sequel/model/associations.rb', line 452

def remove_method
  :"remove_#{singularize(self[:name])}"
end

#remove_should_check_existing? ⇒ Boolean

Whether to check that an object to be disassociated is already associated to this object, false by default.

Returns:

  • (Boolean) 


457
458
459
 
# File 'lib/sequel/model/associations.rb', line 457

def remove_should_check_existing?
  false
end

#returns_array? ⇒ Boolean

Whether this association returns an array of objects instead of a single object, true by default.

Returns:

  • (Boolean) 


463
464
465
 
# File 'lib/sequel/model/associations.rb', line 463

def returns_array?
  true
end

#select ⇒ Object

The columns to select when loading the association.



468
469
470
 
# File 'lib/sequel/model/associations.rb', line 468

def select
  self[:select]
end

#set_reciprocal_to_self? ⇒ Boolean

Whether to set the reciprocal association to self when loading associated records, false by default.

Returns:

  • (Boolean) 


474
475
476
 
# File 'lib/sequel/model/associations.rb', line 474

def set_reciprocal_to_self?
  false
end

#setter_method ⇒ Object

Name symbol for the setter association method



479
480
481
 
# File 'lib/sequel/model/associations.rb', line 479

def setter_method
  :"#{self[:name]}="
end

#slice_range(limit_and_offset = limit_and_offset()) ⇒ Object

The range used for slicing when using the :ruby eager limit strategy.



484
485
486
487
488
489
 
# File 'lib/sequel/model/associations.rb', line 484

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